IO
读入优化
char Getchar(){
static char now[1<<20],*S,*T;
if (T==S){
T=(S=now)+fread(now,1,1<<20,stdin);
if (T==S) return EOF;
}
return *S++;
}
int read(){
int x=0,f=1;
char ch=Getchar();
while (ch<'0'||ch>'9'){
if (ch=='-') f=-1;
ch=Getchar();
}
while (ch<='9'&&ch>='0') x=x*10+ch-'0',ch=Getchar();
return x*f;
}
char readop(){
char ch=Getchar();
while (ch<'A'||ch>'Z') ch=Getchar();
return ch;
}
输出优化
char now[1<<20],*S=now;
void pc(const char c) {
if (S-now==(1<<20)) fwrite(now,1,1<<20,stdout),S=now;
*S++=c;
}
void write(int x) {
static int sta[35];
if (x<0){
pc('-');
x=-x;
}
int top=0;
do{
sta[top++]=x%10;
x/=10;
} while(x);
while (top) pc(sta[--top]+'0');
}
void myfflush(){
fwrite(now,1,S-now,stdout);
}
数学
取模优化
inline int add(int x,int y){ return x+y>=Mod?x+y-Mod:x+y;}
inline int dec(int x,int y){ return x-y<0?x-y+Mod:x-y;}
inline int mul(int x,int y){ return 1ll*x*y%Mod;}
组合数
fac[0]=1; for (int i=1;i<=10000000;i++) fac[i]=fac[i-1]*i%Mod;
inv[1]=1; for (int i=2;i<=10000000;i++) inv[i]=(Mod-Mod/i)*inv[Mod%i]%Mod;
inv[0]=1; for (int i=1;i<=10000000;i++) inv[i]=inv[i-1]*inv[i]%Mod;
ll C(int n,int m){
if (n<m) return 0;
return 1ll*fac[n]*inv[m]%Mod*inv[n-m]%Mod;
}
快速幂
ll qpow(ll x,ll a){//或 ll qpow(ll x,ll a,ll Mod)
ll res=1;
while (a){
if (a&1) res=res*x%Mod;
x=x*x%Mod; a>>=1;
}
return res;
}
gcd, lcm 和 exgcd
ll gcd(ll a,ll b){
if (!b) return a;
return gcd(b,a%b);
}
ll lcm(ll a,ll b){ return 1ll*a/gcd(a,b)*b;}
ll exgcd(ll a,ll b,ll &x,ll &y){
if (!b){
x=1; y=0;
return a;
}
ll g=exgcd(b,a%b,y,x); y-=a/b*x;
return g;
}
CRT
求解 $x\equiv a_i \pmod {b_i}$，满足 $(b_i,b_j)=1$。
ll mul(ll a,ll b,ll mod){
if (a<b) swap(a,b);
ll ans=0;
while (b){
if (b&1) ans=(ans+a)%mod;
a=(a<<1)%mod; b>>=1;
}
return ans;
}
void exgcd(ll a,ll b,ll &x,ll &y){
if (!b){
x=1; y=0;
return;
}
exgcd(b,a%b,x,y);
ll tmp=x; x=y; y=tmp-a/b*y;
}
ll CRT(int n,ll *a,ll *b){
for (int i=1;i<=n;i++) a[i]=(a[i]%b[i]+b[i])%b[i];
ll x,y;
ll ans=0,lcm=1;
for (int i=1;i<=n;i++) lcm*=b[i];
for (int i=1;i<=n;i++){
ll tmp=lcm/b[i];
exgcd(tmp,b[i],x,y);
x=(x%b[i]+b[i])%b[i];
ans=(ans+mul(mul(tmp,x,lcm),a[i],lcm))%lcm;
}
return (ans+lcm)%lcm;
}
exCRT
求解 $x\equiv a_i \pmod {b_i}$。
推导如下：
- 考虑合并两个方程 $x\equiv a_1(\operatorname{mod} m_1),x\equiv a_2(\operatorname{mod} m_2)$。
- 那么，有 $x=a_1+k_1\times m_1,x=a_2+k_2\times m_2$。
- $k_2\times m_2-k_1\times m_1=a_1-a_2$。
- 令 $c=a_1-a_2$，$g=gcd(m_2,m_1)$。
- 那么，若 $g\nmid c$，则方程无解。否则 $g\mid c,\frac{c}{g}\in \mathcal{Z}$。
- 我们可以用 $exgcd$ 求出 $k_2'\times m_2+k_1'\times m_1=g$ 中满足条件的 $k_1'$。
- 将两边同时乘 $\frac{c}{g}$，即 $k_1',k_2'$ 乘上 $\frac cg$，右边变成 $c$ 。
- 我们得到了 $k_2'\times m_2+k_1'\times m_1=c$ 的解 $k_1'$。可以将 $k_1' \mod m_2$。
- 但是注意，我们的原方程是 $k_2\times m_2-k_1\times m_1=a_1-a_2$，故 $k_1=-k_1'$。
- 也就是 $x=a_1-k_1'\times m_1$。我们就求出了一个解 $x_0$。那么通解是 $x\equiv x_0(\operatorname{mod} \operatorname{lcm}(m_1,m_2))$。
ll exCRT(int n,ll *a,ll *m){
ll M=m[1],A=a[1],x,y,d;
for (int i=2;i<=n;i++){
d=exgcd(M,m[i],x,y);
if ((A-a[i])%d) return -1;
x=(A-a[i])/d*x%m[i];
A-=M*x;
M=M/d*m[i];
A%=M;
}
return (A%M+M)%M;
}
Pollard Rho
- 输出 $n$ 的最大质因子（$n\leq 10^{18}$）
#include<cstdio>
#include<cstdlib>
#include<ctime>
#include<algorithm>
#define ctz __builtin_ctzll
using namespace std;
typedef long long ll;
ll ans;
/*inline ll mul(ll x,ll y,ll Mod){
ll ret=x*y-((ll)((long double)x/Mod*y+0.5))*Mod;
return (ret%Mod+Mod)%Mod;
}*/
inline ll mul(ll x,ll y,ll p){
return (__int128)x*y%p;
}
inline ll qpow(ll x,ll a,ll Mod){
ll res=1;
while (a){
if (a&1) res=mul(res,x,Mod);
x=mul(x,x,Mod); a>>=1;
}
return res;
}
inline ll rdm(){ return 1ll*rand()<<31|rand();}
ll gcd(ll x,ll y){
if (!y) return x;
return gcd(y,x%y);
}
bool Miller_Rabin(ll n){
if (n==2||n==3) return true;
if (!(n&1)||(n==1)||!(n%3)) return false;
ll p=n-1,m=0;
while (!(p&1)) p>>=1,++m;
int Case=8;
while (Case--){
ll lst=qpow(rdm()%(n-1)+1,p,n),now=lst;
for (int i=1;i<=m;i++){
now=mul(now,now,n);
if (now==1&&lst!=1&&lst!=n-1) return false;
lst=now;
}
if (now!=1) return false;
}
return true;
}
ll Pollard_Rho(ll n,int c){
ll i=1,k=2,x=rand()%(n-1)+1,y=x,sum=1;
while (true){
i++; x=(mul(x,x,n)+c)%n;
sum=mul(sum,(y-x+n)%n,n);
if (x==y||!sum) return n;
if (i==k||i%127==0){
int d=gcd(sum,n);
if (d!=1) return d;
if (i==k){ y=x; k<<=1;}
}
}
}
void work(ll n){
if (n<=ans) return;
if (Miller_Rabin(n)){
ans=max(ans,n);
return;
}
ll tmp=n;
while (tmp==n) tmp=Pollard_Rho(n,rand()%n);
while (n%tmp==0) n/=tmp;
work(tmp); work(n);
}
int main(){
srand(time(NULL));
int T; ll x;
scanf("%d",&T);
while (T--){
scanf("%lld",&x);
if (Miller_Rabin(x)){ puts("Prime"); continue;}
ans=0; work(x);
printf("%lld\n",ans);
}
return 0;
}
//贴个超级短的：
ll pollardRho(ll n, int a){
ll x=2,y=2,d=1;
while (d==1){
x=(x*x+a)%n;
y=(y*y+a)%n; y=(y*y+a)%n;
d=gcd(abs(x-y),n);
}
if (d==n) return pollardRho(n,a+1);
return d;
}
求单个 phi
int getphi(int x){
int ans=x;
for (int i=2;i*i<=x;i++)
if (x%i==0){
ans=1ll*ans*(i-1)/i;
while (x%i==0) x/=i;
}
if (x>1) ans=1ll*ans*(x-1)/x;
return ans;
}
质因数分解
vector<int> getfac(int x){
vector<int> fac;
for (int i=2;i*i<=x;i++)
if (x%i==0){
fac.push_back(i);
while (x%i==0) x/=i;
}
if (x!=1) fac.push_back(x);
return fac;
}
欧拉筛
最小质因子
void sieve(int n){
//注意，1不是质数
for (int i=2;i<=n;i++){
if (!lst[i]){
lst[i]=i;
prime[++cnt]=i;
}
for (int j=1;j<=cnt&&i*prime[j]<=n;j++){
lst[i*prime[j]]=prime[j];
if (i%prime[j]==0) break;
}
}
}
mu/phi
void sieve(int n){
vis[1]=1;//注意，1不是质数
phi[1]=0; mu[1]=1;
for (int i=2;i<=n;i++){
if (!vis[i]){
p[++cnt]=i;
phi[i]=i-1;
mu[i]=-1;
}
for (int j=1;j<=cnt&&i*p[j]<=n;j++){
vis[i*p[j]]=true;
if (i%p[j]==0){
phi[i*p[j]]=phi[i]*p[j];
mu[i*p[j]]=0;
break;
}
phi[i*p[j]]=phi[i]*(p[j]-1);
mu[i*p[j]]=-mu[i];
}
}
}
BSGS
int BSGS(ll a,ll b){
int blo=(int)(sqrt(p)+1);
ll base=b;
for (int i=0;i<blo;i++){
hs[base]=i;
base=base*a%Mod;
}
ll tmp=1;
base=qpow(a,blo);
for (int i=1;i<=blo+1;i++){
tmp=tmp*base%Mod;
int t=tmp;
if (hs.count(t)) return i*blo-hs[t];
}
return -1;
}
求原根
int primitive_root(){
int phi=getphi(p);
vector<int> fac=getfac(phi);
for (int i=1;i<p;i++){
if (gcd(i,p)!=1) continue;
bool flag=true;
for (int v:fac)
if (qpow(i,phi/v,p)==1){
flag=false;
break;
}
if (flag) return i;
}
return -1;
}
数据结构
树状数组
单点加，区间求和
void add(int *tree,int x,int y){
for (;x<=N;x+=x&-x) tree[x]+=y;
}
int getsum(int *tree,int x){
int sum=0;
for (;x;x-=x&(-x)) sum+=tree[x];
return sum;
}
区间加，区间求和
$$
b[i]=a[i]-a[i-1]
$$
$$
\begin{align}
&a[1] + a[2] + ... + a[n]\
=& (b[1]) + (b[1]+b[2]) + ... + (b[1]+b[2]+...+b[n])\
=& nb[1] + (n-1)b[2] +... +b[n]\
=& n * (b[1]+b[2]+...+b[n]) - (0b[1]+1b[2]+...+(n-1)b[n])
\end{align*}
$$
$$
sum1[i] = \sum b[i],sum2[i] = \sum b[i]*(i-1)
$$
void change(int x,int y){
for (int i=x;i<=n;i+=(i&-i)){
sum1[i]+=y;
sum2[i]+=y*(x-1);
}
}
void range_change(int l,int r,int y){
change(l,y);
change(r+1,-y);
}
int query(int x){
int res=0;
for (int i=x;i>=1;i-=(i&-i)) res+=x*sum1[i]-sum2[i];
return res;
}
int range_query(int l,int r){ return query(r)-query(l-1);}
void init(){
for (int i=1;i<=n;i++) change(i,a[i]-a[i-1]);
//[l,r] +x range_change(l,r,x);
//sum(l,r) range_query(l,r)
return 0;
}
线段树
区间加，区间求和
#include<cstdio>
#define ls ((now)<<1)//左儿子
#define rs ((now)<<1|1)//右儿子
using namespace std;
const int MAXN=110000;
typedef long long ll;
int n,m;
ll a[MAXN];//n->区间长度，m->询问个数，a->区间初始值
struct node{
ll val,add;//线段树的值，加法标记
} tree[MAXN<<2];
void pushup(int now){//上传标记
tree[now].val=tree[ls].val+tree[rs].val;
}
void pushdown(int now,int l,int r){//下传标记
int mid=(l+r)>>1;
//更新实际值
tree[ls].val+=tree[now].add*(mid-l+1);
tree[rs].val+=tree[now].add*(r-mid);
//下传加法标记
tree[ls].add+=tree[now].add;
tree[rs].add+=tree[now].add;
//清空当前标记
tree[now].add=0;
}
void buildtree(int now,int l,int r){//建树
//零标记
tree[now].add=0;
if (l==r){
tree[now].val=a[l];//初始化
return;
}
int mid=(l+r)>>1;
buildtree(ls,l,mid); buildtree(rs,mid+1,r);//建子树
pushup(now);//上传更新
}
void change(int now,int l,int r,int x,int y,ll k){
if (l>r||x>y) return;
if (l==x&&r==y){
tree[now].add+=k;//更新加法标记
tree[now].val+=k*(r-l+1);//更新值
return;
}
int mid=(l+r)>>1; pushdown(now,l,r);//先下传
if (y<=mid) change(ls,l,mid,x,y,k);//更新左子树
else if (x>mid) change(rs,mid+1,r,x,y,k);//更新右子树
else change(ls,l,mid,x,mid,k),change(rs,mid+1,r,mid+1,y,k);//更新左右子树
pushup(now);//上传标记
}
ll query(int now,int l,int r,int x,int y){
if (l>r||x>y) return 0;
if (l==x&&r==y) return tree[now].val;//返回实际值
int mid=(l+r)>>1; pushdown(now,l,r);//先下传
if (y<=mid) return query(ls,l,mid,x,y);//询问左子树
else if (x>mid) return query(rs,mid+1,r,x,y);//询问右子树
else return query(ls,l,mid,x,mid)+query(rs,mid+1,r,mid+1,y);//将左右子树的询问答案相加
pushup(now);//上传标记
}
int main(){
scanf("%d%d",&n,&m);
for (int i=1;i<=n;i++) scanf("%lld",&a[i]);//读入初始值
int op,x,y; ll k;
buildtree(1,1,n);//建树
while (m--){
scanf("%d%d%d",&op,&x,&y);
if (op==1){//1代表加
scanf("%lld",&k);
change(1,1,n,x,y,k);
} else printf("%lld\n",query(1,1,n,x,y));//其它数代表询问
}
return 0;
}
splay
#include<cstdio>
#include<algorithm>
using namespace std;
const int INF=1e9;
int n,m,op,x,a[110000];
int root,sz,tag[110000],ch[110000][2],f[110000],cnt[110000],key[110000],size[110000];
void clear(int x){
ch[x][0]=ch[x][1]=f[x]=cnt[x]=key[x]=size[x]=0;
}
int get(int x){
return ch[f[x]][1]==x;
}
void update(int x){
if (x){
size[x]=cnt[x];
if (ch[x][0]) size[x]+=size[ch[x][0]];
if (ch[x][1]) size[x]+=size[ch[x][1]];
}
}
void pushdown(int x){
if (x&&tag[x]){
tag[ch[x][0]]^=1;
tag[ch[x][1]]^=1;
swap(ch[x][0],ch[x][1]);
tag[x]=0;
}
}
void rotate(int x){
pushdown(f[x]); pushdown(x);
int fa=f[x],gfa=f[fa],dir=get(x);
ch[fa][dir]=ch[x][dir^1]; f[ch[fa][dir]]=fa;
f[fa]=x; ch[x][dir^1]=fa;
f[x]=gfa;
if (gfa) ch[gfa][ch[gfa][1]==fa]=x;
update(fa); update(x);
}
void splay(int x,int goal=0){
for (int fa;(fa=f[x])!=goal;rotate(x))
if (f[fa]!=goal)
rotate((get(x)==get(fa))?fa:x);
if (!goal) root=x;
}
int build(int l,int r,int fa){
if (l>r) return 0;
int mid=(l+r)>>1;
int now=++sz;
key[now]=a[mid]; f[now]=fa;
cnt[now]=1; tag[now]=0;
ch[now][0]=build(l,mid-1,now);
ch[now][1]=build(mid+1,r,now);
update(now);
return now;
}
void insert(int v){
if (!root){
root=++sz;
ch[sz][0]=ch[sz][1]=f[sz]=0;
key[sz]=v; cnt[sz]=size[sz]=1;
return;
}
int now=root,fa=0;
while (true){
if (key[now]==v){
cnt[now]++;
update(now); update(fa);
splay(now);
break;
}
fa=now;
now=ch[now][key[now]<v];
if (!now){
sz++;
ch[sz][0]=ch[sz][1]=0; key[sz]=v;
size[sz]=1; cnt[sz]=1;
f[sz]=fa; ch[fa][key[fa]<v]=sz;
update(fa);
splay(sz);
break;
}
}
}
int Rank(int v){
int ans=0,now=root;
while (true){
if (v<key[now]) now=ch[now][0];
else{
ans+=(ch[now][0]?size[ch[now][0]]:0);
if (v==key[now]){
splay(now);
return ans+1;
}
ans+=cnt[now];
now=ch[now][1];
}
}
}
int find(int x){
int now=root;
while (true){
pushdown(now);
if (ch[now][0]&&x<=size[ch[now][0]]) now=ch[now][0];
else{
int temp=(ch[now][0]?size[ch[now][0]]:0)+cnt[now];
if (x<=temp) return now;//key[now];
x-=temp; now=ch[now][1];
}
}
}
int pre(){
int now=ch[root][0];
while (ch[now][1]) now=ch[now][1];
return now;
}
int next(){
int now=ch[root][1];
while (ch[now][0]) now=ch[now][0];
return now;
}
void del(int x){
Rank(x);
if (cnt[root]>1){
cnt[root]--;
update(root);
return;
}
if (!ch[root][0]&&!ch[root][1]){
clear(root);
root=0;
return;
}
if (!ch[root][0]){
int oldroot=root;
root=ch[root][1];
f[root]=0;
clear(oldroot);
return;
}
else if (!ch[root][1]){
int oldroot=root;
root=ch[root][0];
f[root]=0;
clear(oldroot);
return;
}
int leftbig=pre(),oldroot=root;
splay(leftbig);
f[ch[oldroot][1]]=root; ch[root][1]=ch[oldroot][1];
clear(oldroot);
update(root);
return;
}
void print(int now){
pushdown(now);
if (ch[now][0]) print(ch[now][0]);
if (key[now]!=-INF&&key[now]!=INF)
printf("%d ",key[now]);
if (ch[now][1]) print(ch[now][1]);
}
void reverse(int x,int y){//翻转[x,y]
int a=find(x);
int b=find(y+2);
splay(a); splay(b,a);
tag[ch[ch[root][1]][0]]^=1;
}
int main(){
scanf("%d",&n);
insert(-INF); insert(INF);
for (int i=1;i<=n;i++){
scanf("%d%d",&op,&x);
switch (op){
case 1:
insert(x);
break;
case 2:
del(x);
break;
case 3:
printf("%d\n",Rank(x)-1);
break;
case 4:
printf("%d\n",key[find(x+1)]);
break;
case 5:
insert(x);
printf("%d\n",key[pre()]);
del(x);
break;
case 6:
insert(x);
printf("%d\n",key[next()]);
del(x);
break;
}
}
return 0;
}
左偏树
struct pq{
int v[110000];
int l[110000],r[110000],d[110000];
int merge(int x,int y){
if (!x||!y) return x|y;
if (v[x]<v[y]) swap(x,y);
r[x]=merge(r[x],y);
if (d[r[x]]>d[l[x]]) swap(l[x],r[x]);
d[x]=d[r[x]]+1;
return x;
}
void pop(int &x){ x=merge(l[x],r[x]);}
int top(int x){ return v[x];}
} que;
LCT（Link-Cut Tree）
易错点
- 把 fa[x] 和 f[x] 混起来写
- access 中加注释的地方写成 nroot(x)
- link 的时候写成 f[y]=x
数组版
#include<cstdio>
#include<algorithm>
#define ls c[x][0]
#define rs c[x][1]
using namespace std;
int n,m,type,x,y,f[310000],c[310000][2],v[310000],s[310000],st[310000];
bool r[310000];
bool nroot(int x){
return x==c[f[x]][0]||x==c[f[x]][1];
}
void pushup(int x){
s[x]=s[ls]^s[rs]^v[x];
}
void pushr(int x){
swap(ls,rs);
r[x]^=1;
}
void pushdown(int x){
if (r[x]){
if (ls) pushr(ls);
if (rs) pushr(rs);
r[x]=0;
}
}
int dir(int x){ return c[f[x]][1]==x;}
void rotate(int x){
int y=f[x],z=f[y],k=dir(x),w=c[x][!k];
if (nroot(y)) c[z][dir(y)]=x;
c[x][!k]=y; c[y][k]=w;
if (w) f[w]=y;
f[y]=x; f[x]=z;
pushup(y);
}
void splay(int x){
int y=x,z=0;
st[++z]=y;
while (nroot(y)) st[++z]=y=f[y];
while (z) pushdown(st[z--]);
while (nroot(x)){
y=f[x];
if (nroot(y)) rotate(dir(x)!=dir(y)?x:y);
rotate(x);
}
pushup(x);
}
void access(int x){
for (int y=0;x;y=x,x=f[y]){//注意此处，x是打通到整棵树的根的路径，所以是;x;而不是;nroot(x);。
splay(x);
rs=y; pushup(x);
}
}
void makeroot(int x){ access(x); splay(x); pushr(x);}
int findroot(int x){
access(x); splay(x);
while (ls){
pushdown(x); x=ls;
}
splay(x);
return x;
}
void split(int x,int y){ makeroot(x); access(y); splay(y);}
void link(int x,int y){
makeroot(x);
if (findroot(y)!=x) f[x]=y;
}
void cut(int x,int y){
makeroot(x);
if (findroot(y)==x&&f[y]==x&&!c[y][0]){
f[y]=0; c[x][1]=0;
pushup(x);
}
}
int main(){
scanf("%d%d",&n,&m);
for (int i=1;i<=n;i++) scanf("%d",&v[i]);
while (m--){
scanf("%d%d%d",&type,&x,&y);
switch (type){
case 0: split(x,y); printf("%d\n",s[y]); break;
case 1: link(x,y); break;
case 2: cut(x,y); break;
case 3: splay(x); v[x]=y; break;
}
}
return 0;
}
指针版
#include<bits/stdc++.h>
int n,q,u[110000],v[110000];
template <typename T>
class LCT{
struct node{
node *ch[2],*fa,*pathfa;
T val,sum,max;
bool rev;
node(T v=0){ rev=false; val=sum=max=v; ch[0]=ch[1]=fa=pathfa=NULL;}
bool dir(){ return this==fa->ch[1];}
void pushup(){
sum=val;
if (ch[0]!=NULL) sum+=ch[0]->sum;
if (ch[1]!=NULL) sum+=ch[1]->sum;
max=val;
if (ch[0]!=NULL) max=std::max(max,ch[0]->max);
if (ch[1]!=NULL) max=std::max(max,ch[1]->max);
}
void pushdown(){
if (rev){
std::swap(ch[0],ch[1]);
if (ch[0]!=NULL) ch[0]->rev^=1;
if (ch[1]!=NULL) ch[1]->rev^=1;
rev=false;
}
}
void rotate(){
node *y=fa,*z=fa->fa;
if (z!=NULL) z->pushdown();
y->pushdown(); pushdown();
std::swap(pathfa,y->pathfa);//!!!!!!
int k=dir();
if (z!=NULL) z->ch[y->dir()]=this;
fa=z;
y->ch[k]=ch[k^1];
if (ch[k^1]) ch[k^1]->fa=y;
ch[k^1]=y; y->fa=this;
y->pushup(); pushup();
}
void splay(){
while (fa!=NULL){
if (fa->fa!=NULL){
fa->fa->pushdown(); fa->pushdown();
if (dir()==fa->dir()) fa->rotate();
else rotate();
}
rotate();
}
}
void expose(){//使当前点是重链上最下面一个点
splay();
pushdown();
if (ch[1]){
ch[1]->fa=NULL;
ch[1]->pathfa=this;
ch[1]=NULL;
pushup();
}
}
bool splice(){//将当前这条路径和上面一条路径拼起来
splay();
if (pathfa==NULL) return false;
pathfa->expose();
pathfa->ch[1]=this; fa=pathfa;
pathfa=NULL; fa->pushup();
return true;
}
void access(){//将这个点到根的路径存到一个splay中
expose();
while (splice());
}
void evert(){//把一个点作为整棵树的根
access();
splay(); rev^=1;
}
node* findroot(){
access(); splay();
node *x=this;
x->pushdown();
while (x->ch[0]) x=x->ch[0],x->pushdown();
x->splay(); return x;
}
T querymax(){
access(); splay();
return max;
}
T querysum(){
access(); splay();
return sum;
}
} *p[110000];
public:
void evert(int u,T k){
p[u]=new node(k);
}
bool link(int u,int v){
p[v]->evert();
if (p[u]->findroot()==p[v]) return false;
p[v]->pathfa=p[u];
return true;
}
bool cut(int u,int v){
p[u]->evert();
p[v]->access(); p[v]->splay();
// p[v].pushdown();????
if (p[v]->ch[0]!=p[u]) return false;
p[v]->ch[0]->fa=NULL; p[v]->ch[0]=NULL;
p[v]->pushup(); return true;
}
T querymax(int u,int v){
p[u]->evert();
return p[v]->querymax();
}
T querysum(int u,int v){
p[u]->evert();
return p[v]->querysum();
}
void change(int u,T k){
p[u]->splay();
p[u]->val=k;
p[u]->pushup();
}
};
LCT<int> tree;
int main(){
scanf("%d",&n); int x;
for (int i=1;i<n;i++) scanf("%d%d",&u[i],&v[i]);
for (int i=1;i<=n;i++){
scanf("%d",&x);
tree.evert(i,x);
}
for (int i=1;i<n;i++) tree.link(u[i],v[i]);
scanf("%d",&q);
char op[11]; int u,v;
while (q--){
scanf("%s%d%d",op,&u,&v);
if (op[0]=='C') tree.change(u,v);
else if (op[1]=='S') printf("%d\n",tree.querysum(u,v));
else if (op[1]=='M') printf("%d\n",tree.querymax(u,v));
}
return 0;
}
虚树
来自 luogu2495 的某篇题解
#include<bits/stdc++.h>
using namespace std;
#define il inline
#define re register
#define debug printf("Now is Line : %d\n",__LINE__)
#define file(a) freopen(#a".in","r",stdin);freopen(#a".out","w",stdout)
#define int long long
#define inf 123456789000000000
#define mod 1000000007
il int read()
{
re int x = 0, f = 1; re char c = getchar();
while(c < '0' || c > '9') { if(c == '-') f = -1; c = getchar();}
while(c >= '0' && c <= '9') x = x * 10 + c - 48, c = getchar();
return x * f;
}
#define maxn 250005
struct edge
{
int v, w, next;
}e[maxn << 1];
int n, m, head[maxn], cnt, is[maxn], mi[maxn], dfn[maxn], col, t;
int size[maxn], fa[maxn], top[maxn], son[maxn], dep[maxn], s[maxn];
vector<int>v[maxn];
il void add(int u, int v, int w)
{
e[++ cnt] = (edge){v, w, head[u]};
head[u] = cnt;
}
il bool cmp(int a, int b){return dfn[a] < dfn[b];}
il void dfs1(int u, int fr)
{
size[u] = 1, fa[u] = fr, dep[u] = dep[fr] + 1;
for(re int i = head[u]; i; i = e[i].next)
{
int v = e[i].v;
if(v == fr) continue;
mi[v] = min(mi[u], e[i].w);
dfs1(v, u), size[u] += size[v];
if(size[son[u]] < size[v]) son[u] = v;
}
}
il void dfs2(int u, int fr)
{
top[u] = fr, dfn[u] = ++ col;
if(!son[u]) return;
dfs2(son[u], fr);
for(re int i = head[u]; i; i = e[i].next)
{
int v = e[i].v;
if(v != fa[u] && v != son[u]) dfs2(v, v);
}
}
il int lca(int a, int b)
{
while(top[a] != top[b]) dep[top[a]] > dep[top[b]] ? a = fa[top[a]] : b = fa[top[b]];
return dep[a] < dep[b] ? a : b;
}
il void push(int x)
{
if(t == 1) {s[++ t] = x;return;}
int l = lca(x, s[t]);
if(l == s[t]) return;
while(t > 1 && dfn[s[t - 1]] >= dfn[l]) v[s[t - 1]].push_back(s[t]), --t;
if(s[t] != l) v[l].push_back(s[t]), s[t] = l;
s[++ t] = x;
}
il int dp(int u)
{
if(v[u].size() == 0) return mi[u];
int temp = 0;
for(re int i = 0; i < v[u].size(); ++ i) temp += dp(v[u][i]);
v[u].clear();
return min(mi[u], temp);
}
signed main()
{
file(a);
n = read();
for(re int i = 1; i < n; ++ i)
{
int u = read(), v = read(), w = read();
add(u, v, w), add(v, u, w);
}
mi[1] = inf, dfs1(1, 0), dfs2(1, 1);
int T = read();
while(T --)
{
m = read();
for(re int i = 1; i <= m; ++ i) is[i] = read();
sort(is + 1, is + m + 1, cmp);
s[t = 1] = 1;
for(re int i = 1; i <= m; ++ i) push(is[i]);
while(t > 0) v[s[t - 1]].push_back(s[t]), --t;
printf("%lld\n", dp(1));
}
return 0;
}
网络流
最大流
dinic
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int INF=0x3f3f3f3f;
int n,m,s,t,vis[11000],dep[11000]; ll maxflow;
int edgenum=1,F[210000],V[210000],Next[210000],Head[11000],cur[11000];
void addedge(int u,int v,int f){
V[++edgenum]=v; F[edgenum]=f;
Next[edgenum]=Head[u];
Head[u]=edgenum;
}
void Add(int u,int v,int f){
addedge(u,v,f);
addedge(v,u,0);
}
bool bfs(){
for (int i=1;i<=n;i++) vis[i]=false,dep[i]=INF;
//如果不是 1..n，且s最小t最大，改为 for (int i=s;i<=t;i++)
dep[s]=0;
vis[s]=true;
queue<int> que;
que.push(s);
while (!que.empty()){
int u=que.front(); que.pop();
vis[u]=false;
for (int e=Head[u];e;e=Next[e]){
int v=V[e];
if (dep[v]>dep[u]+1&&F[e]){
dep[v]=dep[u]+1;
if (!vis[v]){
que.push(v);
vis[v]=true;
}
}
}
}
return dep[t]!=INF;
}
int dfs(int u,int flow){
if (u==t){
maxflow+=flow;
return flow;
}
int used=0;
for (int &e=cur[u];e;e=Next[e]){
int v=V[e];
if (F[e]&&dep[v]==dep[u]+1){
int minflow=dfs(v,min(flow-used,F[e]));
F[e]-=minflow; F[e^1]+=minflow; used+=minflow;
if (used==flow) break;
}
}
return used;
}
int dinic(){
while (bfs()){
for (int i=1;i<=n;i++) cur[i]=Head[i];
while (dfs(s,INF));
}
return maxflow;
}
int main(){
scanf("%d%d%d%d",&n,&m,&s,&t);
int u,v,f;
for (int i=1;i<=m;i++){
scanf("%d%d%d",&u,&v,&f);
Add(u,v,f);
}
dinic();
printf("%lld\n",maxflow);
return 0;
}
ISAP
#include<bits/stdc++.h>
using namespace std;
const int INF=0x3f3f3f3f;
int n,m,s,t,gap[11000],cur[11000],d[11000],que[11000];
int edgenum,vet[210000],val[210000],Next[210000],Head[11000];
void addedge(int u,int v,int cost){
vet[++edgenum]=v; val[edgenum]=cost;
Next[edgenum]=Head[u]; Head[u]=edgenum;
}
void bfs(){
memset(gap,0,sizeof(gap));
memset(d,0,sizeof(d));
d[t]=1; gap[1]++;
int head=1,tail=1; que[1]=t;
while (head<=tail){
int u=que[head++];
for (int e=Head[u];e;e=Next[e])
if (!d[vet[e]]){
d[vet[e]]=d[u]+1;
gap[d[vet[e]]]++;
que[++tail]=vet[e];
}
}
}
int dfs(int u,int flow){
if (u==t) return flow;
int used=0;
for (int &e=cur[u];e;e=Next[e])
if (d[u]==d[vet[e]]+1){
int tmp=dfs(vet[e],min(flow,val[e]));
used+=tmp; flow-=tmp;
val[e]-=tmp; val[e^1]+=tmp;
if (!flow) return used;
}
if (!(--gap[d[u]])) d[s]=n+1;
d[u]++; gap[d[u]]++; cur[u]=Head[u];
return used;
}
int maxflow(){
bfs();
for (int i=1;i<=n;i++) cur[i]=Head[i];
int ans=dfs(s,INF);
while (d[s]<=n) ans+=dfs(s,INF);
return ans;
}
int main(){
scanf("%d%d%d%d",&n,&m,&s,&t);
int u,v,cost; edgenum=1;
for (int i=1;i<=m;i++){
scanf("%d%d%d",&u,&v,&cost);
addedge(u,v,cost); addedge(v,u,0);
}
printf("%d\n",maxflow());
return 0;
}
最小费用最大流
EK+SPFA
#include<bits/stdc++.h>
using namespace std;
const int INF=0x3f3f3f3f;
int n,m,s,t,ans,maxflow;
int vis[5100],dis[5100],lst[5100];
int edgenum=1,F[110000],V[110000],Next[110000],W[110000],Head[5100],cur[5100];
void addedge(int u,int v,int f,int w){
V[++edgenum]=v; W[edgenum]=w; F[edgenum]=f;
Next[edgenum]=Head[u];
Head[u]=edgenum;
}
void Add(int u,int v,int f,int w){
addedge(u,v,f,w);
addedge(v,u,0,-w);
}
bool spfa(){
for (int i=1;i<=n;i++) vis[i]=false,dis[i]=INF;
dis[s]=0; vis[s]=true;
queue<int> que;
que.push(s);
while (!que.empty()){
int u=que.front(); que.pop();
vis[u]=false;
for (int e=Head[u];e;e=Next[e]){
int v=V[e];
if (dis[v]>dis[u]+W[e]&&F[e]){
dis[v]=dis[u]+W[e];
lst[v]=e;
if (!vis[v]){
que.push(v);
vis[v]=true;
}
}
}
}
return dis[t]!=INF;
}
int mincostmaxflow(){
while (spfa()){
int tmp=INF;
for (int i=t;i!=s;i=V[lst[i]^1]) tmp=min(tmp,F[lst[i]]);
for (int i=t;i!=s;i=V[lst[i]^1]) F[lst[i]]-=tmp,F[lst[i]^1]+=tmp;
ans+=dis[t]*tmp; maxflow+=tmp;
}
return maxflow;
}
int main(){
scanf("%d%d%d%d",&n,&m,&s,&t);
int u,v,f,w;
for (int i=1;i<=m;i++){
scanf("%d%d%d%d",&u,&v,&f,&w);
Add(u,v,f,w);
}
mincostmaxflow();
printf("%d %d\n",maxflow,ans);
return 0;
}
EK+1 次 SPFA+dijkstra（Johnson）
#include<bits/stdc++.h>
using namespace std;
typedef pair<int,int> pii;
const int INF=0x3f3f3f3f;
int n,m,s,t,ans,maxflow;
int vis[5100],dis[5100],lst[5100],h[5100];
int edgenum=1,F[110000],V[110000],Next[110000],W[110000],Head[5100],cur[5100];
void addedge(int u,int v,int f,int w){
V[++edgenum]=v; W[edgenum]=w; F[edgenum]=f;
Next[edgenum]=Head[u];
Head[u]=edgenum;
}
void Add(int u,int v,int f,int w){
addedge(u,v,f,w);
addedge(v,u,0,-w);
}
bool dijkstra(){
for (int i=1;i<=n;i++) vis[i]=false,dis[i]=INF;
dis[s]=0;
priority_queue<pii> que; que.push(pii(0,s));
while (!que.empty()){
int u=que.top().second; que.pop();
if (vis[u]) continue;
vis[u]=true;
for (int e=Head[u];e;e=Next[e]){
int v=V[e];
if (dis[v]>dis[u]+W[e]+h[u]-h[v]&&F[e]){
dis[v]=dis[u]+W[e]+h[u]-h[v]; lst[v]=e;
que.push(pii(-dis[v],v));
}
}
}
return dis[t]!=INF;
}
bool spfa(){
for (int i=1;i<=n;i++) vis[i]=false,dis[i]=INF;
dis[s]=0; vis[s]=true;
queue<int> que; que.push(s);
while (!que.empty()){
int u=que.front(); que.pop();
vis[u]=false;
for (int e=Head[u];e;e=Next[e]){
int v=V[e];
if (dis[v]>dis[u]+W[e]&&F[e]){
dis[v]=dis[u]+W[e]; lst[v]=e;
if (!vis[v]){
que.push(v);
vis[v]=true;
}
}
}
}
return dis[t]!=INF;
}
int mincostmaxflow(){
spfa();
while (dijkstra()){
int tmp=INF;
for (int i=t;i!=s;i=V[lst[i]^1]) tmp=min(tmp,F[lst[i]]);
for (int i=t;i!=s;i=V[lst[i]^1]) F[lst[i]]-=tmp,F[lst[i]^1]+=tmp;
ans+=(h[t]-h[s]+dis[t])*tmp; maxflow+=tmp;
for (int i=1;i<=n;i++) h[i]+=dis[i];
}
return maxflow;
}
int main(){
scanf("%d%d%d%d",&n,&m,&s,&t);
int u,v,f,w;
for (int i=1;i<=m;i++){
scanf("%d%d%d%d",&u,&v,&f,&w);
Add(u,v,f,w);
}
mincostmaxflow();
printf("%d %d\n",maxflow,ans);
return 0;
}
dinic
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<queue>
using namespace std;
const int INF=0x3f3f3f3f;
int n,m,s,t;
int ans,maxflow;
int vis[5100];//是否到达过该点
int dist[5100];
int edgenum=1,F[110000],V[110000],Next[110000],W[110000],Head[5100];
//f:最大流量（flow），w:单位费用
void addedge(int u,int v,int f,int w){
V[++edgenum]=v; W[edgenum]=w; F[edgenum]=f;
Next[edgenum]=Head[u];
Head[u]=edgenum;
}
void Add(int u,int v,int f,int w){
addedge(u,v,f,w);
addedge(v,u,0,-w);
}
bool spfa(){
memset(vis,false,sizeof(vis));
memset(dist,0x3f,sizeof(dist));
dist[s]=0;
vis[s]=true;
queue<int> que;
que.push(s);
while (!que.empty()){
int u=que.front(); que.pop();
vis[u]=false;
for (int e=Head[u];e;e=Next[e]){
int d=V[e];
if (dist[d]>dist[u]+W[e]&&F[e]){
dist[d]=dist[u]+W[e];
if (!vis[d]){
que.push(d);
vis[d]=true;
}
}
}
}
return dist[t]<INF;
}
int dfs(int u,int flow){
if (u==t){
vis[t]=true; maxflow+=flow;
return flow;
}
int used=0;
vis[u]=true;
for (int e=Head[u];e;e=Next[e]){
int d=V[e];
if ((!vis[d]||d==t)&&F[e]&&dist[d]==dist[u]+W[e]){
int minflow=dfs(d,min(flow-used,F[e]));
if (minflow!=0) ans+=W[e]*minflow,F[e]-=minflow,F[e^1]+=minflow,used+=minflow;
if (used==flow) break;
}
}
return used;
}
int mincostmaxflow(){
while (spfa()){
vis[t]=1;
while (vis[t]){
memset(vis,false,sizeof(vis));
dfs(s,INF);
}
}
return maxflow;
}
int main(){
n=read(),m=read(),s=read(),t=read();
int u,v,f,w;
for (register int i=1;i<=m;i++){
u=read(),v=read(),f=read(),w=read();
Add(u,v,f,w);
}
mincostmaxflow();
printf("%d %d\n",maxflow,ans);
return 0;
}
最小费用流
EK+dijkstra
正确性可能存在问题（顶标大小越界）？
/*
CF164C
有n个任务，每个任务给定一个开始时间si、持续时间ti、所得收益ci；
有k台机器，每台机器一个时刻只能处理一个任务；
求如何安排，使得收益和最大。
*/
#include<bits/stdc++.h>
using namespace std;
typedef pair<int,int> pii;
const int INF=0x3f3f3f3f;
int n,k,s,t,ans,maxflow,u[5100],v[5100],c[5100];
int cnt,num[5100],h[5100],vis[5100],dis[5100],lst[5100];
int edgenum=1,F[110000],V[110000],Next[110000],W[110000],Head[5100],cur[5100];
void addedge(int u,int v,int f,int w){
V[++edgenum]=v; W[edgenum]=w; F[edgenum]=f;
Next[edgenum]=Head[u];
Head[u]=edgenum;
}
void Add(int u,int v,int f,int w){
if (w<0){
num[u]-=f; num[v]+=f;
addedge(v,u,f,-w);
// cerr<<"#"<<v<<' '<<u<<' '<<f<<' '<<-w<<endl;
addedge(u,v,0,w); ans+=w*f;
} else{
addedge(u,v,f,w);
// cerr<<"#"<<u<<' '<<v<<' '<<f<<' '<<w<<endl;
addedge(v,u,0,-w);
}
}
bool dijkstra(){
for (int i=s;i<=t;i++) vis[i]=false,dis[i]=INF;
dis[s]=0;
priority_queue<pii> que; que.push(pii(0,s));
while (!que.empty()){
int u=que.top().second; que.pop();
if (vis[u]) continue;
vis[u]=true;
for (int e=Head[u];e;e=Next[e]){
int v=V[e];
if (dis[v]>dis[u]+W[e]+h[u]-h[v]&&F[e]){
dis[v]=dis[u]+W[e]+h[u]-h[v]; lst[v]=e;
que.push(pii(-dis[v],v));
}
}
}
return dis[t]!=INF;
}
int mincostmaxflow(){
while (dijkstra()){
int tmp=INF;
for (int i=t;i!=s;i=V[lst[i]^1]) tmp=min(tmp,F[lst[i]]);
for (int i=t;i!=s;i=V[lst[i]^1]) F[lst[i]]-=tmp,F[lst[i]^1]+=tmp;
ans+=(h[t]-h[s]+dis[t])*tmp; maxflow+=tmp;
for (int i=s;i<=t;i++) h[i]+=dis[i];
}
return maxflow;
}
int main(){
scanf("%d%d",&n,&k);
for (int i=1;i<=n;i++){
scanf("%d%d%d",&u[i],&v[i],&c[i]); v[i]+=u[i];
num[++cnt]=u[i]; num[++cnt]=v[i];
}
sort(num+1,num+cnt+1); cnt=unique(num+1,num+cnt+1)-num-1;
s=0; t=cnt+1;
for (int i=1;i<=n;i++){
u[i]=lower_bound(num+1,num+cnt+1,u[i])-num;
v[i]=lower_bound(num+1,num+cnt+1,v[i])-num;
}
for (int i=1;i<=cnt;i++) num[i]=0;
num[1]+=k; num[cnt]-=k;
for (int i=1;i<=n;i++) Add(u[i],v[i],1,-c[i]);
for (int i=1;i<=cnt;i++){
if (num[i]>0) Add(s,i,num[i],0);
if (num[i]<0) Add(i,t,-num[i],0);
}
for (int i=1;i<cnt;i++) Add(i,i+1,k,0);
mincostmaxflow();
// printf("%d\n",-ans);
for (int i=1;i<=n;i++)
printf("%d ",F[i<<1]);
return 0;
}
无向图欧拉回路
// 求出欧拉图中的一条欧拉回路
#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int head[100010], ver[1000010], Next[1000010], tot; // 邻接表
int stack[1000010], ans[1000010]; // 模拟系统栈，答案栈
bool vis[1000010];
int n, m, top, t;
void add(int x, int y) {
ver[++tot] = y, Next[tot] = head[x], head[x] = tot;
}
void euler() {
stack[++top] = 1;
while (top > 0) {
int x = stack[top], i = head[x];
// 找到一条尚未访问的边
while (i && vis[i]) i = Next[i];
// 沿着这条边模拟递归过程，标记该边，并更新表头
if (i) {
stack[++top] = ver[i];
head[x] = Next[i];
vis[i] = vis[i ^ 1] = true;
}
// 与x相连的所有边均已访问，模拟回溯过程，并记录于答案栈中
else {
top--;
ans[++t] = x;
}
}
}
int main() {
cin >> n >> m;
tot = 1;
for (int i = 1; i <= m; i++) {
int x, y;
scanf("%d%d", &x, &y);
add(x, y), add(y, x);
}
euler();
for (int i = t; i; i--) printf("%d\n", ans[i]);
}
Tarjan
无向图桥/边双
#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<vector>
using namespace std;
const int SIZE = 100010;
int head[SIZE], ver[SIZE * 2], Next[SIZE * 2];
int dfn[SIZE], low[SIZE], c[SIZE];
int n, m, tot, num, dcc, tc;
bool bridge[SIZE * 2];
int hc[SIZE], vc[SIZE * 2], nc[SIZE * 2];
void add(int x, int y) {
ver[++tot] = y, Next[tot] = head[x], head[x] = tot;
}
void add_c(int x, int y) {
vc[++tc] = y, nc[tc] = hc[x], hc[x] = tc;
}
void tarjan(int x, int in_edge) {
dfn[x] = low[x] = ++num;
for (int i = head[x]; i; i = Next[i]) {
int y = ver[i];
if (!dfn[y]) {
tarjan(y, i);
low[x] = min(low[x], low[y]);
if (low[y] > dfn[x])
bridge[i] = bridge[i ^ 1] = true;
}
else if (i != (in_edge ^ 1))
low[x] = min(low[x], dfn[y]);
}
}
void dfs(int x) {
c[x] = dcc;
for (int i = head[x]; i; i = Next[i]) {
int y = ver[i];
if (c[y] || bridge[i]) continue;
dfs(y);
}
}
int main() {
cin >> n >> m;
tot = 1;
for (int i = 1; i <= m; i++) {
int x, y;
scanf("%d%d", &x, &y);
add(x, y), add(y, x);
}
for (int i = 1; i <= n; i++)
if (!dfn[i]) tarjan(i, 0);
for (int i = 2; i < tot; i += 2)
if (bridge[i])
printf("%d %d\n", ver[i ^ 1], ver[i]);
for (int i = 1; i <= n; i++)
if (!c[i]) {
++dcc;
dfs(i);
}
printf("There are %d e-DCCs.\n", dcc);
for (int i = 1; i <= n; i++)
printf("%d belongs to DCC %d.\n", i, c[i]);
tc = 1;
for (int i = 2; i <= tot; i++) {
int x = ver[i ^ 1], y = ver[i];
if (c[x] == c[y]) continue;
add_c(c[x], c[y]);
}
printf("缩点之后的森林，点数 %d，边数 %d\n", dcc, tc / 2);
for (int i = 2; i < tc; i += 2)
printf("%d %d\n", vc[i ^ 1], vc[i]);
}
无向图割点/点双
#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<vector>
using namespace std;
const int SIZE = 100010;
int head[SIZE], ver[SIZE * 2], Next[SIZE * 2];
int dfn[SIZE], low[SIZE], stack[SIZE], new_id[SIZE], c[SIZE];
int n, m, tot, num, root, top, cnt, tc;
bool cut[SIZE];
vector<int> dcc[SIZE];
int hc[SIZE], vc[SIZE * 2], nc[SIZE * 2];
void add(int x, int y) {
ver[++tot] = y, Next[tot] = head[x], head[x] = tot;
}
void add_c(int x, int y) {
vc[++tc] = y, nc[tc] = hc[x], hc[x] = tc;
}
void tarjan(int x) {
dfn[x] = low[x] = ++num;
stack[++top] = x;
if (x == root && head[x] == 0) { // 孤立点 !!!!!!!!!!!!!!!!!!!!!!
dcc[++cnt].push_back(x);
return;
}
int flag = 0;
for (int i = head[x]; i; i = Next[i]) {
int y = ver[i];
if (!dfn[y]) {
tarjan(y);
low[x] = min(low[x], low[y]);
if (low[y] >= dfn[x]) {
flag++;
if (x != root || flag > 1) cut[x] = true;
cnt++;
int z;
do {
z = stack[top--];
dcc[cnt].push_back(z);
} while (z != y);
dcc[cnt].push_back(x);
}
}
else low[x] = min(low[x], dfn[y]);
}
}
int main() {
cin >> n >> m;
tot = 1;
for (int i = 1; i <= m; i++) {
int x, y;
scanf("%d%d", &x, &y);
if (x == y) continue;
add(x, y), add(y, x);
}
for (int i = 1; i <= n; i++)
if (!dfn[i]) root = i, tarjan(i);
for (int i = 1; i <= n; i++)
if (cut[i]) printf("%d ", i);
puts("are cut-vertexes");
for (int i = 1; i <= cnt; i++) {
printf("v-DCC #%d:", i);
for (int j = 0; j < dcc[i].size(); j++)
printf(" %d", dcc[i][j]);
puts("");
}
// 给每个割点一个新的编号(编号从cnt+1开始)
num = cnt;
for (int i = 1; i <= n; i++)
if (cut[i]) new_id[i] = ++num;
// 建新图，从每个v-DCC到它包含的所有割点连边
tc = 1;
for (int i = 1; i <= cnt; i++)
for (int j = 0; j < dcc[i].size(); j++) {
int x = dcc[i][j];
if (cut[x]) {
add_c(i, new_id[x]);
add_c(new_id[x], i);
}
else c[x] = i; // 除割点外，其它点仅属于1个v-DCC
}
printf("缩点之后的森林，点数 %d，边数 %d\n", num, tc / 2);
printf("编号 1~%d 的为原图的v-DCC，编号 >%d 的为原图割点\n", cnt, cnt);
for (int i = 2; i < tc; i += 2)
printf("%d %d\n", vc[i ^ 1], vc[i]);
}
有向图强连通分量
void tarjan(int u)
{
int v;
dfn[u]=low[u]=++idx;//每次dfs，u的次序号增加1
s.push(u);//将u入栈
ins[u]=1;//标记u在栈内
for(int i=head[u];i!=-1;i=e[i].next)//访问从u出发的边
{
v=e[i].v;
if(!dfn[v])//如果v没被处理过
{
tarjan(v);//dfs(v)
low[u]=min(low[u],low[v]);//u点能到达的最小次序号是它自己能到达点的最小次序号和连接点v能到达点的最小次序号中较小的
}
else if(ins[v])low[u]=min(low[u],dfn[v]);//如果v在栈内，u点能到达的最小次序号是它自己能到达点的最小次序号和v的次序号中较小的
}
if(dfn[u]==low[u])//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
{
Bcnt++;
do
{
v=s.top();
s.pop();
ins[v]=0;
Belong[v]=Bcnt;
}while(u != v);
}
}
二分图匹配
匈牙利算法
最大匹配
bool dfs(int x) {
for (int i = head[x], y; i; i = next[i])
if (!visit[y = ver[i]]) {
visit[y] = 1;
if (!match[y] || dfs(match[y])) {
match[y]=x;
return true;
}
}
return false;
}
for (int i = 1; i <= n; i++) {
memset(visit, 0, sizeof(visit));
if (dfs(i)) ans++;
}
KM 算法
最大权匹配
#include<bits/stdc++.h>
using namespace std;
const int INF=0x3f3f3f3f;
int n,m,w[110][110],label_x[110],label_y[110],match[110],slack[110],lst[110];
bool vis[110];
int main(){
scanf("%d%d",&n,&m);
for (int i=1;i<=n;i++)
for (int j=1;j<=n;j++){
scanf("%d",&w[i][j]);
label_x[i]=max(label_x[i],w[i][j]);
}
for (int u=1;u<=n;u++){
memset(slack,0x3f,sizeof(slack));
memset(vis,false,sizeof(vis));
match[0]=u; int i,j;
for (i=0;match[i];i=j){
vis[i]=true; int x=match[i],delta=INF;
for (int y=1;y<=n;y++)
if (!vis[y]){
int tmp=label_x[x]+label_y[y]-w[x][y];
if (tmp<slack[y]){
slack[y]=tmp;
lst[y]=i;
}
if (delta>slack[y]){
delta=slack[y];
j=y;
}
}
for (int y=0;y<=n;y++)
if (vis[y]){
label_x[match[y]]-=delta;
label_y[y]+=delta;
} else slack[y]-=delta;
}
while (i) match[i]=match[lst[i]],i=lst[i];
}
int ans=0;
for (int i=1;i<=n;i++) ans+=label_x[i]+label_y[i];
printf("%d\n",ans);
// printf("%d\n",ans*n);
// if (m)
// for (int i=1;i<=n;i++){
// for (int j=1;j<=n;j++)
// printf("%d ",label_x[i]+label_y[j]);
// putchar('\n');
// }
return 0;
}
多项式
暴力操作
struct poly{
vector<int> v;
poly(){ v.clear();}
inline int size(){ return v.size();}
friend poly operator+(poly A,poly B){
int lenA=A.v.size()-1,lenB=B.v.size()-1;
int len=max(lenA,lenB);
A.v.resize(len+1); B.v.resize(len+1);
poly C; C.v.resize(len+1);
for (int i=0;i<=len;i++) C.v[i]=add(A.v[i],B.v[i]);
return C;
}
friend poly operator*(poly A,int v){
for (int i=0;i<A.size();i++) A.v[i]=mul(A.v[i],v);
return A;
}
friend poly operator*(const poly &A,const poly &B){
int len=A.v.size()+B.v.size()-2;
poly C; C.v.resize(len+1);
for (int i=0;i<(int)A.v.size();i++)
for (int j=0;j<(int)B.v.size();j++)
C.v[i+j]=add(C.v[i+j],mul(A.v[i],B.v[j]));
return C;
}
friend poly operator%(poly A,const poly &B){
int lenA=(int)A.v.size()-1,lenB=(int)B.v.size()-1;
int inv=getinv(B.v[lenB]);
if (lenA<lenB) return A;
for (int i=lenA;i>=lenB;i--)
if (A.v[i]){
int t=mul(A.v[i],inv);
for (int j=i;j>=i-lenB;j--) A.v[j]=dec(A.v[j],mul(t,B.v[lenB-i+j]));
}
A.v.resize(lenB+1); return A;
}
};
poly qpow(poly x,char *a,const poly &M){//a为二进制数
poly res; res.v.clear(); res.v.push_back(1);
for (int i=strlen(a)-1;i>=0;i--){
if (a[i]=='1') res=(res*x)%M;
x=(x*x)%M;
}
return res;
}
FWT
均类似于 FFT/NTT 的三重循环。
Or 卷积，正变换是大的+小的，逆变换是大的-小的。（两个数 Or 起来会变大）。
And 卷积，正变换是小的+大的，逆变换是小的-大的。（两个数 And 起来会变小）。
Xor 卷积，正变换和 FFT/NTT 一样，小的=(X+Y)，大的=(X-Y)。逆变换把结果都/2。
变换完后直接对应位乘即可。
void FWT_or(int *a,int op){
for (int i=1;i<N;i<<=1)
for (int p=i<<1,j=0;j<N;j+=p)
for (int k=0;k<i;++k)
if (op==1) a[i+j+k]=(a[j+k]+a[i+j+k])%Mod;
else a[i+j+k]=(a[i+j+k]+Mod-a[j+k])%Mod;
}
void FWT_and(int *a,int op){
for (int i=1;i<N;i<<=1)
for (int p=i<<1,j=0;j<N;j+=p)
for (int k=0;k<i;++k)
if (op==1) a[j+k]=(a[j+k]+a[i+j+k])%Mod;
else a[j+k]=(a[j+k]+Mod-a[i+j+k])%Mod;
}
void FWT_xor(int *a,int op){
for (int i=1;i<N;i<<=1)
for (int p=i<<1,j=0;j<N;j+=p)
for (int k=0;k<i;k++){
int X=a[j+k],Y=a[i+j+k];
a[j+k]=(X+Y)%Mod; a[i+j+k]=(X+Mod-Y)%Mod;
if (op==-1){
a[j+k]=1ll*a[j+k]*inv2%Mod;
a[i+j+k]=1ll*a[i+j+k]*inv2%Mod;//inv2为2的逆元
}
}
}
FFT
- 首先，重要的一点是
rev[x]=(rev[x>>1]>>1)|((x&1)<<(bit-1))。相当于把它的最后一个位置删去，然后反过来，此时所有位置都往左移了一位，那么右移一位，最后把最后一个位置的数放在最高位。 - 然后，将原序列
x<rev[x]的位置，交换x,rev[x]。（否则会交换两次，相当于没交换）。 - 考虑正变换
- 枚举 mid，表示当前长度的一半。此时，$\omega=\cos \frac{2\pi}{2mid}+sin\frac{2\pi}{2mid}=\cos\frac{\pi}{mid}+sin \frac{\pi}{mid}$。
- 然后枚举起始位置$i$，必须是 $2mid$ 的倍数。
- 初始时，$w=1$，然后，枚举段中的位置 $j$ ，则 $i+j$ 为左边段的真实位置，$i+j+mid$ 是右边段的真实位置。
- $a[i + j] = (X + Y), a[i + j + mid] = w * (X - Y)$，最后$w*=\omega$。
- 接着考虑逆变换，其实就是改变了$\omega$，此时$\omega=cos \frac{\pi}{mid}-i\sin\frac{\pi}{mid}$。最后要把每个数都/n。
#include<cstdio>
#include<cmath>
#include<algorithm>
using namespace std;
const int MAXN=1e7+10;
char Getchar(){
static char now[1<<20],*S,*T;
if (T==S){
T=(S=now)+fread(now,1,1<<20,stdin);
if (T==S) return EOF;
}
return *S++;
}
int read(){
int x=0,f=1;
char ch=Getchar();
while (ch<'0'||ch>'9'){
if (ch=='-') f=-1;
ch=Getchar();
}
while (ch<='9'&&ch>='0') x=x*10+ch-'0',ch=Getchar();
return x*f;
}
const double Pi=acos(-1.0);
struct complex{
double x,y;
complex (double xx=0,double yy=0){ x=xx; y=yy;}
} a[MAXN],b[MAXN];
complex operator+(complex a,complex b){ return complex(a.x+b.x,a.y+b.y);}
complex operator-(complex a,complex b){ return complex(a.x-b.x,a.y-b.y);}
complex operator*(complex a,complex b){ return complex(a.x*b.x-a.y*b.y,a.x*b.y+a.y*b.x);}
int N,M;
int l,r[MAXN];
int len=1;
void FFT(complex *A,int type){
for (int i=0;i<len;i++)
if (i<r[i]) swap(A[i],A[r[i]]);
for (int mid=1;mid<len;mid<<=1){
complex Wn(cos(Pi/mid),type*sin(Pi/mid));
for (int R=mid<<1,j=0;j<len;j+=R){
complex w(1,0);
for (int k=0;k<mid;k++,w=w*Wn){
complex x=A[j+k],y=w*A[j+mid+k];
A[j+k]=x+y; A[j+mid+k]=x-y;
}
}
}
}
int main(){
int N=read(),M=read();
for (int i=0;i<=N;i++) a[i].x=read();
for (int i=0;i<=M;i++) b[i].x=read();
while (len<=N+M) len<<=1,l++;
for (int i=0;i<len;i++) r[i]=(r[i>>1]>>1)|((i&1)<<(l-1));
FFT(a,1); FFT(b,1);
for (int i=0;i<=len;i++) a[i]=a[i]*b[i];
FFT(a,-1);
for (int i=0;i<=N+M;i++) printf("%d ",(int)(a[i].x/len+0.5));
return 0;
}
NTT
- 正变换：改变了 FFT 中的$\omega$，此时$\omega = g ^ \dfrac{\varphi(Mod)}{mid * 2} = g ^ \dfrac{Mod - 1}{mid * 2}$。
- 逆变换：改变了 FFT 中的$\omega$，此时$\omega = \dfrac 1{g ^ \dfrac{\varphi(Mod)}{mid * 2}}=\dfrac 1{g ^ \dfrac{Mod - 1}{mid * 2}}$。
#include<cstdio>
#include<algorithm>
using namespace std;
typedef long long ll;
const int g=3;
const int Mod=998244353;
const int MAXN=2100000;//>n+m上取到2的幂次
int n,m,len,rev[MAXN];
ll a[MAXN],b[MAXN],c[MAXN];
inline ll qpow(ll x,int a){
ll res=1;
while (a){
if (a&1) res=res*x%Mod;
x=x*x%Mod; a>>=1;
}
return res;
}
inline int getinv(int x){ return qpow(x,Mod-2);}
void NTT(ll *a,int inv){
for (int i=0;i<n;i++)
if (i<rev[i]) swap(a[i],a[rev[i]]);
for (int mid=1;mid<n;mid<<=1){
int tmp=qpow(g,(Mod-1)/(mid<<1));
if (inv==-1) tmp=getinv(tmp);
for (int i=0;i<n;i+=mid*2){
ll omega=1;
for (ll j=0;j<mid;j++,omega=omega*tmp%Mod){
int x=a[i+j],y=omega*a[i+j+mid]%Mod;
a[i+j]=(x+y)%Mod,a[i+j+mid]=(x-y+Mod)%Mod;
}
}
}
}
int main(){
scanf("%d%d",&n,&m); n++; m++;
for (int i=0;i<n;i++) scanf("%lld",&a[i]);
for (int i=0;i<m;i++) scanf("%lld",&b[i]);
len=n+m-1;
int bit=0;
while ((1<<bit)<len) bit++;
n=1<<bit;
for (int i=0;i<n;i++) rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));
NTT(a,1); NTT(b,1);
for (int i=0;i<n;i++) a[i]=a[i]*b[i]%Mod;
NTT(a,-1);
ll inv=getinv(n);
for (int i=0;i<len;i++){
c[i]=a[i]*inv%Mod;
printf("%lld ",c[i]);
}
return 0;
}
多项式求逆
- 就一个式子，将变换后的按位乘改为：$b[i] = (2 - c[i] * b[i]) * b[i]$。
递归版
void polymul(vec &a,vec &b,vec &c,int bit){
int n=1<<bit;
for (int i=0;i<n;i++) rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));
NTT(n,a,1); NTT(n,b,1);
for (int i=0;i<n;i++) a[i]=a[i]*b[i]%Mod;
NTT(n,a,-1);
ll inv=getinv(n); c.resize(n);
for (int i=0;i<n;i++) c[i]=a[i]*inv%Mod;
a.clear(); b.clear();
}
void polyinv(int len,int bit,vec &a,vec &b){
int n=1<<bit;
for (int i=0;i<n;i++) rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));
vec c=a; c.resize(len);
NTT(n,c,1); NTT(n,b,1);
for (int i=0;i<n;i++) b[i]=1ll*(Mod+2-1ll*c[i]*b[i]%Mod)%Mod*b[i]%Mod;
NTT(n,b,-1); b.resize(len);
ll inv=getinv(n);
for (int i=0;i<len;i++) b[i]=b[i]*inv%Mod;
}
int getbit(int x){
int bit=1;
while ((1<<bit)<x) bit++;
return bit;
}
void getinv(int n,vec &a,vec &b){
if (n==1){
b.resize(1);
b[0]=getinv(a[0]);
return;
}
getinv((n+1)>>1,a,b);
int bit=getbit(n<<1);
polyinv(n,bit,a,b);
}
非递归版
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int Mod=998244353;
const int inv2=(Mod+1)/2;
int rev[810000];
int f[810000],g[810000];
ll fac[110000],inv[110000];
ll qpow(ll x,ll a){
ll res=1;
while (a){
if (a&1) res=res*x%Mod;
x=x*x%Mod; a>>=1;
}
return res;
}
void NTT(int *a,int n,int op){
for (int i=0;i<n;i++)
if (i<rev[i]) swap(a[i],a[rev[i]]);
for (int mid=1;mid<n;mid<<=1){
int tmp=qpow(3,(Mod-1)/(mid<<1));
if (op==-1) tmp=qpow(tmp,Mod-2);
for (int i=0;i<n;i+=(mid<<1)){
ll omega=1;
for (int j=0;j<mid;j++,omega=omega*tmp%Mod){
int x=a[i+j],y=omega*a[i+j+mid]%Mod;
a[i+j]=(x+y)%Mod; a[i+j+mid]=(x-y+Mod)%Mod;
}
}
}
if (op==1) return;
ll inv=qpow(n,Mod-2);
for (int i=0;i<n;i++) a[i]=a[i]*inv%Mod;
}
void polysqr(int *a,int n){
int len; for (len=1;len<(n<<1);len<<=1);
for (int i=0;i<len;i++) rev[i]=(rev[i>>1]>>1)|((i&1)?(len>>1):0);
NTT(a,len,1);
for (int i=0;i<len;i++) a[i]=1ll*a[i]*a[i]%Mod;
NTT(a,len,-1);
for (int i=n;i<len;i++) a[i]=0;
}
void polyinv(int *a,int *b,int n){
static int A[810000],B[810000];
b[0]=qpow(a[0],Mod-2);
for (int mid=2;mid<(n<<1);mid<<=1){
int len=mid<<1;
for (int i=0;i<mid;i++) A[i]=a[i],B[i]=b[i];
for (int i=mid;i<len;i++) A[i]=0,B[i]=0;
for (int i=0;i<len;i++) rev[i]=(rev[i>>1]>>1)|((i&1)?mid:0);
NTT(A,len,1); NTT(B,len,1);
for (int i=0;i<len;i++) b[i]=1ll*(Mod+2-1ll*A[i]*B[i]%Mod)*B[i]%Mod;
NTT(b,len,-1);
for (int i=mid;i<len;i++) b[i]=0;
}
}
void polysqrt(int *a,int *b,int n){
static int A[810000],B[810000];
b[0]=qpow(a[0],Mod-2);
for (int mid=2;mid<(n<<1);mid<<=1){
int len=mid<<1;
for (int i=0;i<mid;i++) A[i]=a[i];
for (int i=mid;i<len;i++) A[i]=0;
polyinv(b,B,mid);
for (int i=0;i<len;i++) rev[i]=(rev[i>>1]>>1)|((i&1)?mid:0);
NTT(A,len,1); NTT(B,len,1);
for (int i=0;i<len;i++) A[i]=1ll*A[i]*B[i]%Mod;
NTT(A,len,-1);
for (int i=0;i<mid;i++) b[i]=1ll*(b[i]+A[i])%Mod*inv2%Mod;
for (int i=mid;i<len;i++) b[i]=0;
}
}
int T,n;
int main(){
fac[0]=1; for (int i=1;i<=100000;i++) fac[i]=fac[i-1]*i%Mod;
inv[1]=1; for (int i=2;i<=100000;i++) inv[i]=(Mod-Mod/i)*inv[Mod%i]%Mod;
inv[0]=1; for (int i=1;i<=100000;i++) inv[i]=inv[i-1]*inv[i]%Mod;
for (int i=0;i<=100000;i++) f[i]=qpow(qpow(3,1ll*i*(i-1)/2),Mod-2)*inv[i]%Mod;
polysqr(f,100001);
for (int i=0;i<=100000;i++) f[i]=qpow(3,1ll*i*(i-1)/2)*f[i]%Mod;
polysqrt(f,g,100001);
scanf("%d",&T);
while (T--){
scanf("%d",&n);
printf("%lld\n",1ll*g[n]*fac[n]%Mod);
}
return 0;
}
拉格朗日插值
- $\displaystyle f(x)=\sum{i=1}^n y_i\prod{i\not= j} \frac{x-x_j}{x_i-x_j} $
scanf("%lld%lld",&n,&k);//求f(k)
for (int i=1;i<=n;i++) scanf("%lld%lld",&x[i],&y[i]);//f(x[i])=y[i]
ll s1,s2,ans=0;
for (int i=1;i<=n;i++){
s1=y[i]%Mod; s2=1ll;
for (int j=1;j<=n;j++)
if (i!=j){
s1=s1*(k-x[j])%Mod;
s2=s2*(x[i]-x[j])%Mod;
}
s1=(s1+Mod)%Mod; s2=(s2+Mod)%Mod;
ans=(ans+s1*inv(s2))%Mod;
}
printf("%lld\n",ans);
//1..n
int Lagrange(int k){
if (k<=n) return f[k];
int res=0;
for (int i=1;i<=n;i++){
int s=1;
for (int j=0;j<=n;j++){
if (i==j) continue;
s=1ll*s*((k-j)%Mod+Mod)%Mod;
if (i>j) s=1ll*s*inv[i-j]%Mod;
else s=(Mod-1ll*s*inv[j-i]%Mod)%Mod;
}
res=(res+1ll*f[i]*s%Mod)%Mod;
}
return res;
}
下降幂多项式乘法
#include<cstdio>
#include<algorithm>
using namespace std;
typedef long long ll;
const int Mod=998244353;
const int G=3;
int n,m,len;
ll f[610000],g[610000],s[610000];
ll fac[610000],invfac[610000];
int rev[610000];
char Getchar(){
static char now[1<<20],*S,*T;
if (T==S){
T=(S=now)+fread(now,1,1<<20,stdin);
if (T==S) return EOF;
}
return *S++;
}
int read(){
int x=0,f=1;
char ch=Getchar();
while (ch<'0'||ch>'9'){
if (ch=='-') f=-1;
ch=Getchar();
}
while (ch<='9'&&ch>='0') x=x*10+ch-'0',ch=Getchar();
return x*f;
}
char readop(){
char ch=Getchar();
while (ch<'A'||ch>'Z') ch=Getchar();
return ch;
}
ll qpow(ll x,ll a){
ll res=1;
while (a){
if (a&1) res=res*x%Mod;
x=x*x%Mod; a>>=1;
}
return res;
}
inline int add(int x,int y){return x+y>=Mod?x+y-Mod:x+y;}
inline int dec(int x,int y){return x-y<0?x-y+Mod:x-y;}
inline int mul(int x,int y){return 1ll*x*y%Mod;}
inline ll getinv(int x){ return qpow(x,Mod-2);}
void NTT(ll *a,int inv){
for (int i=0;i<len;i++)
if (i<rev[i]) swap(a[i],a[rev[i]]);
for (int mid=1;mid<len;mid<<=1){
int tmp=qpow(G,(Mod-1)/(mid<<1));
if (inv==-1) tmp=getinv(tmp);
for (int i=0;i<len;i+=(mid<<1)){
ll omega=1;
for (ll j=0;j<mid;j++,omega=mul(omega,tmp)){
int x=a[i+j],y=mul(omega,a[i+j+mid]);
a[i+j]=add(x,y),a[i+j+mid]=dec(x,y);
}
}
}
if (inv==-1){
ll inv=getinv(len);
for (int i=0;i<n;i++) a[i]=mul(a[i],inv);
}
}
void FDT(ll *f,int inv){
if (inv==1)
for (int i=0;i<n;i++) s[i]=invfac[i];
else
for (int i=0;i<n;i++)
if (i&1) s[i]=Mod-invfac[i];
else s[i]=invfac[i];
for (int i=n;i<len;i++) s[i]=0;
NTT(f,1); NTT(s,1);
for (int i=0;i<len;i++) f[i]=mul(f[i],s[i]);
NTT(f,-1);
for (int i=n;i<len;i++) f[i]=0;
}
int main(){
n=read()+1; m=read()+1;
for (int i=0;i<n;i++) f[i]=read();
for (int i=0;i<m;i++) g[i]=read();
n=n+m-1;
int bit=0; while ((1<<bit)<n+n) bit++;
len=1<<bit;
for (int i=0;i<len;i++) rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));
fac[0]=1; for (int i=1;i<=len;i++) fac[i]=fac[i-1]*i%Mod;
invfac[1]=1; for (int i=2;i<=len;i++) invfac[i]=(Mod-Mod/i)*invfac[Mod%i]%Mod;
invfac[0]=1; for (int i=1;i<=len;i++) invfac[i]=invfac[i-1]*invfac[i]%Mod;
FDT(f,1); FDT(g,1);
for (int i=0;i<n;i++) f[i]=mul(mul(f[i],g[i]),fac[i]);
FDT(f,-1);
for (int i=0;i<n;i++) printf("%lld ",f[i]);
return 0;
}
多项式除法
- $A(x)/B(x)$
- $A$的最高次项为 $x^n$，$B$ 的最高次项为 $x^m$。
- 把 $A,B$ 翻转，$B$ 的最高此项改为 $x^{n-m}$。
- 求出 $B$ 的逆，和 $A$ 乘起来，再取 $x^0...x^{n-m}$。再翻转 ，输出。
#include<cstdio>
#include<vector>
#include<algorithm>
//#define int long long
#define ls (now<<1)
#define rs (now<<1|1)
using namespace std;
typedef long long ll;
typedef vector<int> poly;
const int Mod=998244353;
const int G=3; const int invG=332748118;
int n,m,a[310000],rev[310000],ans[310000];
poly f,g;
char Getchar(){
static char now[1<<20],*S,*T;
if (T==S){
T=(S=now)+fread(now,1,1<<20,stdin);
if (T==S) return EOF;
}
return *S++;
}
int read(){
int x=0,f=1;
char ch=Getchar();
while (ch<'0'||ch>'9'){
if (ch=='-') f=-1;
ch=Getchar();
}
while (ch<='9'&&ch>='0') x=x*10+ch-'0',ch=Getchar();
return x*f;
}
inline int add(int x,int y){return x+y>=Mod?x+y-Mod:x+y;}
inline int dec(int x,int y){return x-y<0?x-y+Mod:x-y;}
inline int mul(int x,int y){return 1ll*x*y%Mod;}
ll qpow(ll x,ll a){
ll res=1;
while (a){
if (a&1) res=res*x%Mod;
x=x*x%Mod; a>>=1;
}
return res;
}
inline ll getinv(int x){ return qpow(x,Mod-2);}
void NTT(poly &a,int len,int inv){
a.resize(len);
for (int i=0;i<len;i++)
if (i<rev[i]) swap(a[i],a[rev[i]]);
for (int mid=1;mid<len;mid<<=1){
int tmp=qpow(G,(Mod-1)/(mid<<1));
if (inv==-1) tmp=getinv(tmp);
// printf("%d ",(Mod-1)/(mid<<1));
for (int i=0;i<len;i+=(mid<<1)){
ll omega=1;
for (ll j=0;j<mid;j++,omega=mul(omega,tmp)){
int x=a[i+j],y=mul(omega,a[i+j+mid]);
a[i+j]=add(x,y),a[i+j+mid]=dec(x,y);
}
}
}
if (inv==-1){
ll inv=getinv(len);
for (int i=0;i<len;i++) a[i]=mul(a[i],inv);
}
}
void mult(poly a,poly b,poly &c,int n){
int bit=0; while ((1<<bit)<n+n) bit++;
int len=1<<bit;
for (int i=0;i<len;i++) rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));
NTT(a,len,1); NTT(b,len,1);
c.resize(len);
for (int i=0;i<len;i++) c[i]=mul(a[i],b[i]);
NTT(c,len,-1);
}
void polyinv(int len,int bit,poly &a,poly &b){
int n=1<<bit;
for (int i=0;i<n;i++) rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));
poly c=a; c.resize(len); b.resize(len);
NTT(c,n,1); NTT(b,n,1);
for (int i=0;i<n;i++) b[i]=1ll*(Mod+2-1ll*c[i]*b[i]%Mod)%Mod*b[i]%Mod;
NTT(b,n,-1); b.resize(len);
}
int getbit(int x){
int bit=1;
while ((1<<bit)<x) bit++;
return bit;
}
void getinv(int n,poly &a,poly &b){
if (n==1){
b.resize(1);
b[0]=getinv(a[0]);
return;
}
getinv((n+1)>>1,a,b);
int bit=getbit(n<<1);
polyinv(n,bit,a,b);
}
poly c,d;
poly getdiv(poly a,poly b){
int n=a.size()-1,m=b.size()-1;
if (n<m){
d.resize(1); d[0]=0;
return d;
}
reverse(a.begin(),a.end());
reverse(b.begin(),b.end());
b.resize(n-m+1); c.clear();
getinv(n-m+1,b,c); d.clear();
mult(c,a,d,n+(n-m+1)); d.resize(n-m+1);
reverse(d.begin(),d.end());
return d;
}
poly ans1,tmp,ans2;
void getmod(poly &a,poly b,poly &c){
int n=a.size()-1,m=b.size()-1;
if (n<m) return;
ans1=getdiv(a,b);
mult(ans1,b,tmp,n+m);
c.resize(m);
for (int i=0;i<m;i++) c[i]=dec(a[i],tmp[i]);
}
int main(){
n=read(); m=read();
f.resize(n+1); g.resize(m+1);
for (int i=0;i<=n;i++) f[i]=read();
for (int i=0;i<=m;i++) g[i]=read();
getmod(f,g,ans2); ans1.resize(n-m);
for (int i=0;i<=n-m;i++) printf("%d ",ans1[i]); putchar('\n');
for (int i=0;i<m;i++) printf("%d ",ans2[i]);
return 0;
}
/*
5 1
15466465 9465465 2154654 64546 4546466 8664456
1545 75468
*/
多点求值
#include<cstdio>
#include<vector>
#include<algorithm>
#define ls (now<<1)
#define rs (now<<1|1)
using namespace std;
typedef long long ll;
typedef vector<int> poly;
const int Mod=998244353;
const int G=3; const int invG=332748118;
int n,m,a[310000],rev[310000],ans[310000];
ll Inv[2100000],powG[2100000],powInvG[2100000];
poly f;
char Getchar(){
static char now[1<<20],*S,*T;
if (T==S){
T=(S=now)+fread(now,1,1<<20,stdin);
if (T==S) return EOF;
}
return *S++;
}
int read(){
int x=0,f=1;
char ch=Getchar();
while (ch<'0'||ch>'9'){
if (ch=='-') f=-1;
ch=Getchar();
}
while (ch<='9'&&ch>='0') x=x*10+ch-'0',ch=Getchar();
return x*f;
}
inline int add(int x,int y){return x+y>=Mod?x+y-Mod:x+y;}
inline int dec(int x,int y){return x-y<0?x-y+Mod:x-y;}
inline int mul(int x,int y){return 1ll*x*y%Mod;}
ll qpow(ll x,ll a){
ll res=1;
while (a){
if (a&1) res=res*x%Mod;
x=x*x%Mod; a>>=1;
}
return res;
}
inline ll getinv(const int &x){ return qpow(x,Mod-2);}
void NTT(poly &a,const int &len,const int &inv){
a.resize(len);
for (int i=0;i<len;i++)
if (i<rev[i]) swap(a[i],a[rev[i]]);
for (int mid=1;mid<len;mid<<=1){
int tmp;
if (inv==1) tmp=powG[mid];
else tmp=powInvG[mid];
// int tmp=qpow(G,(Mod-1)/(mid<<1));
// if (inv==-1) tmp=getinv(tmp);
// printf("%d ",(Mod-1)/(mid<<1));
for (int i=0;i<len;i+=(mid<<1)){
ll omega=1;
for (ll j=0;j<mid;j++,omega=mul(omega,tmp)){
int x=a[i+j],y=mul(omega,a[i+j+mid]);
a[i+j]=add(x,y),a[i+j+mid]=dec(x,y);
}
}
}
if (inv==-1){
ll inv=Inv[len];
for (int i=0;i<len;i++) a[i]=mul(a[i],inv);
}
}
/*void NTT(poly &a,int len,int inv){
a.resize(len);
for (int i=0;i<len;i++)
if (i<rev[i]) swap(a[i],a[rev[i]]);
for (int mid=1;mid<len;mid<<=1){
int tmp=qpow(G,(Mod-1)/(mid<<1));
if (inv==-1) tmp=getinv(tmp);
// printf("%d ",(Mod-1)/(mid<<1));
for (int i=0;i<len;i+=(mid<<1)){
ll omega=1;
for (ll j=0;j<mid;j++,omega=mul(omega,tmp)){
int x=a[i+j],y=mul(omega,a[i+j+mid]);
a[i+j]=add(x,y),a[i+j+mid]=dec(x,y);
}
}
}
if (inv==-1){
ll inv=getinv(len);
for (int i=0;i<len;i++) a[i]=mul(a[i],inv);
}
}*/
void mult(poly a,poly b,poly &c,const int &n){
int bit=0; while ((1<<bit)<n) bit++;
int len=1<<bit;
for (int i=0;i<len;i++) rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));
NTT(a,len,1); NTT(b,len,1);
c.resize(len);
for (int i=0;i<len;i++) c[i]=mul(a[i],b[i]);
NTT(c,len,-1);
}
void polyinv(const int &len,const int &bit,poly &a,poly &b){
int n=1<<bit;
for (int i=0;i<n;i++) rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));
poly c=a; c.resize(len); b.resize(len);
NTT(c,n,1); NTT(b,n,1);
for (int i=0;i<n;i++) b[i]=1ll*(Mod+2-1ll*c[i]*b[i]%Mod)%Mod*b[i]%Mod;
NTT(b,n,-1); b.resize(len);
}
inline int getbit(const int &x){
int bit=1;
while ((1<<bit)<x) bit++;
return bit;
}
void getinv(const int &n,poly &a,poly &b){
if (n==1){
b.resize(1);
b[0]=getinv(a[0]);
return;
}
getinv((n+1)>>1,a,b);
int bit=getbit(n<<1);
polyinv(n,bit,a,b);
}
poly c,d;
poly getdiv(poly a,poly b){
int n=a.size()-1,m=b.size()-1;
if (n<m){
d.resize(1); d[0]=0;
return d;
}
reverse(a.begin(),a.end());
reverse(b.begin(),b.end());
b.resize(n-m+1); c.clear();
getinv(n-m+1,b,c); d.clear();
mult(c,a,d,n+(n-m+1)); d.resize(n-m+1);
reverse(d.begin(),d.end());
return d;
}
poly ans1,tmp,ans2;
void getmod(poly a,poly b,poly &c){
while (!b.empty()&&!b.back()) b.pop_back();
int n=a.size()-1,m=b.size()-1;
if (n<m){ c=a; return;}
ans1=getdiv(a,b);
mult(ans1,b,tmp,n+m);
c.resize(m);
for (int i=0;i<m;i++) c[i]=dec(a[i],tmp[i]);
}
poly p[310000];
void getpoly(const int &now,const int &l,const int &r){
if (l==r){
p[now].push_back(dec(0,a[l]));
p[now].push_back(1); return;
}
int mid=(l+r)>>1;
getpoly(ls,l,mid); getpoly(rs,mid+1,r);
mult(p[ls],p[rs],p[now],r-l+2);
}
void solve(const poly &A,const int &now,const int &l,const int &r){
if (r-l<=1000){
for (int i=l;i<=r;i++){
int s=0;
for (int j=A.size()-1;j>=0;j--) s=add(mul(s,a[i]),A[j]);
ans[i]=s;
}
return;
}
poly B;
int mid=(l+r)>>1;
getmod(A,p[ls],B);
solve(B,ls,l,mid);
getmod(A,p[rs],B);
solve(B,rs,mid+1,r);
}
int main(){
for (int mid=1;mid<=2000000;mid<<=1){
powG[mid]=qpow(G,(Mod-1)/(mid<<1));
powInvG[mid]=qpow(powG[mid],Mod-2);
}
Inv[1]=1; for (int i=2;i<=2000000;i++) Inv[i]=(Mod-Mod/i)*Inv[Mod%i]%Mod;
n=read(); m=read(); f.resize(n+1);
for (int i=0;i<=n;i++) f[i]=read();
for (int i=1;i<=m;i++) a[i]=read();
// n=64000; m=64000; f.resize(n+1);
// for (int i=0;i<=n;i++) f[i]=1;
// for (int i=1;i<=m;i++) a[i]=i;
getpoly(1,1,m);
getmod(f,p[1],f);
solve(f,1,1,m);
for (int i=1;i<=m;i++) printf("%d\n",ans[i]);
return 0;
}
ToDo: 多项式快速插值
多项式 ln/exp
#include<cstdio>
#include<vector>
using namespace std;
typedef vector<int> poly;
typedef long long ll;
const int Mod=998244353;
const int G=3;
int n,m,a[310000],rev[310000],ans[310000];
poly f,g;
char Getchar(){
static char now[1<<20],*S,*T;
if (T==S){
T=(S=now)+fread(now,1,1<<20,stdin);
if (T==S) return EOF;
}
return *S++;
}
int read(){
int x=0,f=1;
char ch=Getchar();
while (ch<'0'||ch>'9'){
if (ch=='-') f=-1;
ch=Getchar();
}
while (ch<='9'&&ch>='0') x=x*10+ch-'0',ch=Getchar();
return x*f;
}
inline int add(int x,int y){return x+y>=Mod?x+y-Mod:x+y;}
inline int dec(int x,int y){return x-y<0?x-y+Mod:x-y;}
inline int mul(int x,int y){return 1ll*x*y%Mod;}
ll qpow(ll x,ll a){
ll res=1;
while (a){
if (a&1) res=res*x%Mod;
x=x*x%Mod; a>>=1;
}
return res;
}
inline ll getinv(const int &x){ return qpow(x,Mod-2);}
void NTT(poly &a,int len,int inv){
a.resize(len);
for (int i=0;i<len;i++)
if (i<rev[i]) swap(a[i],a[rev[i]]);
for (int mid=1;mid<len;mid<<=1){
int tmp=qpow(G,(Mod-1)/(mid<<1));
if (inv==-1) tmp=getinv(tmp);
for (int i=0;i<len;i+=(mid<<1)){
ll omega=1;
for (ll j=0;j<mid;j++,omega=mul(omega,tmp)){
int x=a[i+j],y=mul(omega,a[i+j+mid]);
a[i+j]=add(x,y),a[i+j+mid]=dec(x,y);
}
}
}
if (inv==-1){
ll inv=getinv(len);
for (int i=0;i<len;i++) a[i]=mul(a[i],inv);
}
}
void mult(poly a,poly b,poly &c,const int &n){
int bit=0; while ((1<<bit)<n) bit++;
int len=1<<bit;
for (int i=0;i<len;i++) rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));
NTT(a,len,1); NTT(b,len,1);
c.resize(len);
for (int i=0;i<len;i++) c[i]=mul(a[i],b[i]);
NTT(c,len,-1);
}
void polyinv(const int &len,const int &bit,poly &a,poly &b){
int n=1<<bit;
for (int i=0;i<n;i++) rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));
poly c=a; c.resize(len); b.resize(len);
NTT(c,n,1); NTT(b,n,1);
for (int i=0;i<n;i++) b[i]=1ll*(Mod+2-1ll*c[i]*b[i]%Mod)%Mod*b[i]%Mod;
NTT(b,n,-1); b.resize(len);
}
inline int getbit(const int &x){
int bit=1;
while ((1<<bit)<x) bit++;
return bit;
}
void getinv(const int &n,poly &a,poly &b){
if (n==1){
b.resize(1);
b[0]=getinv(a[0]);
return;
}
getinv((n+1)>>1,a,b);
int bit=getbit(n<<1);
polyinv(n,bit,a,b);
}
void Dao(poly &A,poly &B,int len){
for (int i=1;i<len;i++) B[i-1]=1ll*i*A[i]%Mod;
B[len-1]=0;
}
void Jifen(poly &A,poly &B,int len){
for (int i=1;i<len;i++) B[i]=1ll*A[i-1]*getinv(i)%Mod;
B[0]=0;
}
poly A,B,C;
void getln(poly &f,poly &g,int n){
f.resize(n); g.resize(n);
A.resize(n); B.resize(n);
Dao(f,A,n); getinv(n,f,B);
mult(A,B,C,n+n);
Jifen(C,g,n);
}
poly t;
void getexp(const int &n,poly &a,poly &b){
if (n==1){
b.resize(1); b[0]=1;
return;
}
getexp(n>>1,a,b);
getln(b,t,n);
for (int i=0;i<n;i++) t[i]=dec(a[i],t[i]);
t[0]=add(1,t[0]);
mult(t,b,b,n+n); t.clear(); b.resize(n);
}
int main(){
n=read(); f.resize(n);
for (int i=0;i<n;i++) f[i]=read();
for (m=1;m<=n;m<<=1);
f.resize(m);
getexp(m,f,g);
for (int i=0;i<n;i++) printf("%d ",g[i]);
return 0;
}
普通多项式转下降幂多项式
#include<cstdio>
#include<algorithm>
#include<vector>
#define ls (now<<1)
#define rs (now<<1|1)
using namespace std;
typedef long long ll;
typedef vector<int> poly;
const int Mod=998244353;
const int G=3; const int invG=332748118;
int n,m,a[510000],rev[510000],ans[510000];
ll Inv[1100000];
int GPow[2][19][510000];
ll fac[1100000],invfac[1100000];
poly f;
char Getchar(){
static char now[1<<20],*S,*T;
if (T==S){
T=(S=now)+fread(now,1,1<<20,stdin);
if (T==S) return EOF;
}
return *S++;
}
int read(){
int x=0,f=1;
char ch=Getchar();
while (ch<'0'||ch>'9'){
if (ch=='-') f=-1;
ch=Getchar();
}
while (ch<='9'&&ch>='0') x=x*10+ch-'0',ch=Getchar();
return x*f;
}
inline int add(int x,int y){return x+y>=Mod?x+y-Mod:x+y;}
inline int dec(int x,int y){return x-y<0?x-y+Mod:x-y;}
inline int mul(int x,int y){return 1ll*x*y%Mod;}
ll qpow(ll x,ll a){
ll res=1;
while (a){
if (a&1) res=res*x%Mod;
x=x*x%Mod; a>>=1;
}
return res;
}
inline ll getinv(const int &x){ return qpow(x,Mod-2);}
inline void InitG(){
for (int p=1;p<=18;p++) {
int buf1=qpow(G,(Mod-1)/(1<<p));
int buf0=qpow(invG,(Mod-1)/(1<<p));
GPow[1][p][0]=GPow[0][p][0]=1;
for (int i=1;i<(1<<p);i++){
GPow[1][p][i]=1LL*GPow[1][p][i-1]*buf1%Mod;
GPow[0][p][i]=1LL*GPow[0][p][i-1]*buf0%Mod;
}
}
}
void NTT(poly &a,const int &len,int inv){
if (inv==-1) inv=0;
a.resize(len);
for (int i=0;i<len;i++)
if (i<rev[i]) swap(a[i],a[rev[i]]);
/*for (int mid=1;mid<len;mid<<=1){
int tmp;
if (inv==1) tmp=powG[mid];
else tmp=powInvG[mid];
for (int i=0;i<len;i+=(mid<<1)){
ll omega=1;
for (ll j=0;j<mid;j++,omega=mul(omega,tmp)){
int x=a[i+j],y=mul(omega,a[i+j+mid]);
a[i+j]=add(x,y),a[i+j+mid]=dec(x,y);
}
}
}*/
for (int l=2,cnt=1;l<=len;l<<=1,cnt++){
int m=l>>1;
for (int i=0;i<len;i+=l){
int *buf=GPow[inv][cnt];
for (int j=0;j<m;j++,buf++) {
int x=a[i+j],y=1LL*(*buf)*a[i+j+m]%Mod;
a[i+j]=add(x,y),a[i+j+m]=dec(x,y);
}
}
}
if (inv!=1){
ll inv=Inv[len];
for (int i=0;i<len;i++) a[i]=mul(a[i],inv);
}
}
void mult(poly a,poly b,poly &c,const int &n){
int bit=0; while ((1<<bit)<n) bit++;
int len=1<<bit;
for (int i=0;i<len;i++) rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));
NTT(a,len,1); NTT(b,len,1);
c.resize(len);
for (int i=0;i<len;i++) c[i]=mul(a[i],b[i]);
NTT(c,len,-1);
}
void polyinv(const int &len,const int &bit,poly &a,poly &b){
int n=1<<bit;
for (int i=0;i<n;i++) rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));
poly c=a; c.resize(len); b.resize(len);
NTT(c,n,1); NTT(b,n,1);
for (int i=0;i<n;i++) b[i]=mul(dec(2,mul(c[i],b[i])),b[i]);
NTT(b,n,-1); b.resize(len);
}
inline int getbit(const int &x){
int bit=1;
while ((1<<bit)<x) bit++;
return bit;
}
void getinv(const int &n,poly &a,poly &b){
if (n==1){
b.resize(1);
b[0]=getinv(a[0]);
return;
}
getinv((n+1)>>1,a,b);
int bit=getbit(n<<1);
polyinv(n,bit,a,b);
}
poly c,d;
poly getdiv(poly a,poly b){
int n=a.size()-1,m=b.size()-1;
if (n<m){
d.resize(1); d[0]=0;
return d;
}
reverse(a.begin(),a.end());
reverse(b.begin(),b.end());
b.resize(n-m+1); c.clear();
getinv(n-m+1,b,c); d.clear();
mult(c,a,d,n+(n-m+1)); d.resize(n-m+1);
reverse(d.begin(),d.end());
return d;
}
poly ans1,tmp,ans2;
void getmod(poly a,poly b,poly &c){
while (!b.empty()&&!b.back()) b.pop_back();
int n=a.size()-1,m=b.size()-1;
if (n<m){ c=a; return;}
ans1=getdiv(a,b);
mult(ans1,b,tmp,n+m);
c.resize(m);
for (int i=0;i<m;i++) c[i]=dec(a[i],tmp[i]);
}
poly p[510000];
void getpoly(const int &now,const int &l,const int &r){
if (l==r){
p[now].push_back(dec(0,a[l]));
p[now].push_back(1); return;
}
int mid=(l+r)>>1;
getpoly(ls,l,mid); getpoly(rs,mid+1,r);
mult(p[ls],p[rs],p[now],r-l+2);
}
void solve(const poly &A,const int &now,const int &l,const int &r){
if (r-l<=700){
for (int i=l;i<=r;i++){
int s=0;
for (int j=A.size()-1;j>=0;j--) s=add(mul(s,a[i]),A[j]);
ans[i]=s;
}
return;
}
poly B;
int mid=(l+r)>>1;
getmod(A,p[ls],B);
solve(B,ls,l,mid);
getmod(A,p[rs],B);
solve(B,rs,mid+1,r);
}
poly s;
void FDT(poly &f,int len,int inv){
f.resize(len); s.resize(len);
if (inv==1)
for (int i=0;i<n;i++) s[i]=invfac[i];
else
for (int i=0;i<n;i++)
if (i&1) s[i]=Mod-invfac[i];
else s[i]=invfac[i];
for (int i=n;i<len;i++) s[i]=0;
NTT(f,len,1); NTT(s,len,1);
for (int i=0;i<len;i++) f[i]=mul(f[i],s[i]);
NTT(f,len,-1);
for (int i=n;i<len;i++) f[i]=0;
}
int main(){
Inv[1]=1; for (int i=2;i<=1000000;i++) Inv[i]=(Mod-Mod/i)*Inv[Mod%i]%Mod;
InitG();
n=read(); f.resize(n);
// n=100000; f.resize(n);
// for (int i=0;i<n;i++) f[i]=i;
for (int i=0;i<n;i++) f[i]=read();
m=n; for (int i=1;i<=m;i++) a[i]=i-1;
getpoly(1,1,m);
getmod(f,p[1],f);
solve(f,1,1,m);
int bit=0; while ((1<<bit)<n+n) bit++;
int len=1<<bit;
for (int i=0;i<len;i++) rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));
fac[0]=1; for (int i=1;i<=len;i++) fac[i]=fac[i-1]*i%Mod;
invfac[1]=1; for (int i=2;i<=len;i++) invfac[i]=(Mod-Mod/i)*invfac[Mod%i]%Mod;
invfac[0]=1; for (int i=1;i<=len;i++) invfac[i]=invfac[i-1]*invfac[i]%Mod;
f.resize(n);
for (int i=0;i<n;i++) f[i]=mul(ans[i+1],invfac[i]);
FDT(f,len,-1);
for (int i=0;i<n;i++) printf("%d ",f[i]);
return 0;
}
下降幂多项式转普通多项式
#include<cstdio>
#include<vector>
using namespace std;
const int G=3,invG=332748118;
const int Mod=998244353;
typedef long long ll;
typedef vector<int> poly;
struct node{
poly g,f;
};
char Getchar(){
static char now[1<<20],*S,*T;
if (T==S){
T=(S=now)+fread(now,1,1<<20,stdin);
if (T==S) return EOF;
}
return *S++;
}
int read(){
int x=0,f=1;
char ch=Getchar();
while (ch<'0'||ch>'9'){
if (ch=='-') f=-1;
ch=Getchar();
}
while (ch<='9'&&ch>='0') x=x*10+ch-'0',ch=Getchar();
return x*f;
}
inline int add(int x,int y){return x+y>=Mod?x+y-Mod:x+y;}
inline int dec(int x,int y){return x-y<0?x-y+Mod:x-y;}
inline int mul(int x,int y){return 1ll*x*y%Mod;}
ll qpow(ll x,ll a){
ll res=1;
while (a){
if (a&1) res=res*x%Mod;
x=x*x%Mod; a>>=1;
}
return res;
}
inline ll getinv(int x){ return qpow(x,Mod-2);}
int n,GPow[2][20][1100000];
int rev[1100000]; ll fac[1100000],inv[1100000],invfac[1100000];
poly f,tmp,ans;
inline void InitG(){
fac[0]=1; for (int i=1;i<=1000000;i++) fac[i]=fac[i-1]*i%Mod;
inv[1]=1; for (int i=2;i<=1000000;i++) inv[i]=(Mod-Mod/i)*inv[Mod%i]%Mod;
invfac[0]=1; for (int i=1;i<=1000000;i++) invfac[i]=invfac[i-1]*inv[i]%Mod;
for (int p=1;p<=19;p++) {
int buf1=qpow(G,(Mod-1)/(1<<p));
int buf0=qpow(invG,(Mod-1)/(1<<p));
GPow[1][p][0]=GPow[0][p][0]=1;
for (int i=1;i<(1<<p);i++){
GPow[1][p][i]=1LL*GPow[1][p][i-1]*buf1%Mod;
GPow[0][p][i]=1LL*GPow[0][p][i-1]*buf0%Mod;
}
}
}
void NTT(poly &a,const int &len,int inv){
if (inv==-1) inv=0;
a.resize(len);
for (int i=0;i<len;i++)
if (i<rev[i]) swap(a[i],a[rev[i]]);
for (int l=2,cnt=1;l<=len;l<<=1,cnt++){
int m=l>>1;
for (int i=0;i<len;i+=l){
int *buf=GPow[inv][cnt];
for (int j=0;j<m;j++,buf++){
int x=a[i+j],y=1LL*(*buf)*a[i+j+m]%Mod;
a[i+j]=add(x,y),a[i+j+m]=dec(x,y);
}
}
}
if (inv!=1){
ll inv=getinv(len);
for (int i=0;i<len;i++) a[i]=mul(a[i],inv);
}
}
poly A,B;
void mult(int n,int m,const poly &a,const poly &b,poly &c){
n++; m++;
int len=1,bit=0;
while (len<(n+m)) len<<=1,bit++;
A.resize(n); B.resize(m);
for (int i=0;i<n;i++) A[i]=a[i];
for (int i=0;i<m;i++) B[i]=b[i];
c.resize(len);
for (int i=0;i<len;i++) rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));
NTT(A,len,1); NTT(B,len,1);
for (int i=0;i<len;i++) c[i]=1ll*A[i]*B[i]%Mod;
NTT(c,len,-1);
}
poly s;
void ADD(poly &a,const poly &b){
if (b.size()>a.size()) a.resize(b.size());
for (int i=0;i<(int)b.size();i++) a[i]=add(a[i],b[i]);
}
void FDT(poly &f,int len,int inv){
f.resize(len); s.resize(len);
if (inv==1)
for (int i=0;i<n;i++) s[i]=invfac[i];
else
for (int i=0;i<n;i++)
if (i&1) s[i]=Mod-invfac[i];
else s[i]=invfac[i];
for (int i=n;i<len;i++) s[i]=0;
NTT(f,len,1); NTT(s,len,1);
for (int i=0;i<len;i++) f[i]=mul(f[i],s[i]);
NTT(f,len,-1);
f.resize(n);
}
node interpolation(int l,int r,const poly &A,const poly &B){
if (l==r){
node tmp;
tmp.g.clear(); tmp.f.clear();
tmp.g.push_back(dec(0,l)); tmp.g.push_back(1);
tmp.f.push_back(mul(A[l],B[l]));
return tmp;
}
int mid=(l+r)>>1;
node a=interpolation(l,mid,A,B);
node b=interpolation(mid+1,r,A,B);
poly c; mult(mid-l+1,r-mid,a.g,b.g,c);
poly d; mult(mid-l+1,r-mid-1,a.g,b.f,d);
poly e; mult(mid-l,r-mid,a.f,b.g,e);
ADD(d,e);
return (node){c,d};
}
int main(){
InitG();
n=read(); f.resize(n); tmp.resize(n);
for (int i=0;i<n;i++) f[i]=read();
int bit=0; while ((1<<bit)<n+n) bit++;
int len=1<<bit;
for (int i=0;i<len;i++) rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));f.resize(n); tmp.resize(n);
FDT(f,len,1);
for (int i=0;i<n;i++) f[i]=mul(f[i],fac[i]);
for (int i=0;i<n;i++) tmp[i]=mul(invfac[i],((n-i)&1)?invfac[n-i-1]:Mod-invfac[n-i-1]);
ans=interpolation(0,n-1,f,tmp).f;
ans.resize(n);
for (int i=0;i<n;i++) printf("%d ",ans[i]);
return 0;
}
常系数齐次线性递推
#include<cstdio>
#include<vector>
#include<algorithm>
using namespace std;
const int G=3,invG=332748118;
const int Mod=998244353;
typedef long long ll;
typedef vector<int> poly;
char Getchar(){
static char now[1<<20],*S,*T;
if (T==S){
T=(S=now)+fread(now,1,1<<20,stdin);
if (T==S) return EOF;
}
return *S++;
}
int read(){
int x=0,f=1;
char ch=Getchar();
while (ch<'0'||ch>'9'){
if (ch=='-') f=-1;
ch=Getchar();
}
while (ch<='9'&&ch>='0') x=x*10+ch-'0',ch=Getchar();
return x*f;
}
inline int add(int x,int y){return x+y>=Mod?x+y-Mod:x+y;}
inline int dec(int x,int y){return x-y<0?x-y+Mod:x-y;}
inline int mul(int x,int y){return 1ll*x*y%Mod;}
ll qpow(ll x,ll a){
ll res=1;
while (a){
if (a&1) res=res*x%Mod;
x=x*x%Mod; a>>=1;
}
return res;
}
inline ll getinv(int x){ return qpow(x,Mod-2);}
int GPow[2][19][410000];
int rev[410000],f[410000],g[410000];
poly A,B,c,a,b;
inline void InitG(){
for (int p=1;p<=18;p++) {
int buf1=qpow(G,(Mod-1)/(1<<p));
int buf0=qpow(invG,(Mod-1)/(1<<p));
GPow[1][p][0]=GPow[0][p][0]=1;
for (int i=1;i<(1<<p);i++){
GPow[1][p][i]=1LL*GPow[1][p][i-1]*buf1%Mod;
GPow[0][p][i]=1LL*GPow[0][p][i-1]*buf0%Mod;
}
}
}
void NTT(poly &a,const int &len,int inv){
if (inv==-1) inv=0;
a.resize(len);
for (int i=0;i<len;i++)
if (i<rev[i]) swap(a[i],a[rev[i]]);
for (int l=2,cnt=1;l<=len;l<<=1,cnt++){
int m=l>>1;
for (int i=0;i<len;i+=l){
int *buf=GPow[inv][cnt];
for (int j=0;j<m;j++,buf++) {
int x=a[i+j],y=1LL*(*buf)*a[i+j+m]%Mod;
a[i+j]=add(x,y),a[i+j+m]=dec(x,y);
}
}
}
if (inv!=1){
ll inv=getinv(len);
for (int i=0;i<len;i++) a[i]=mul(a[i],inv);
}
}
void mult(int n,int m,const poly &a,const poly &b,poly &c){
int len=1,bit=0;
while (len<(n+m)) len<<=1,bit++;
A.resize(n); B.resize(m);
for (int i=0;i<n;i++) A[i]=a[i];
for (int i=0;i<m;i++) B[i]=b[i];
c.resize(len);
for (int i=0;i<len;i++) rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));
NTT(A,len,1); NTT(B,len,1);
for (int i=0;i<len;i++) c[i]=1ll*A[i]*B[i]%Mod;
NTT(c,len,-1);
}
void PolyInv(int n,poly &a,poly &b){
if (n==1){
b.resize(1);
b[0]=getinv(a[0]);
return;
}
PolyInv((n+1)>>1,a,b);
int len=1,bit=0;
while (len<(n<<1)) len<<=1,bit++;
c.resize(n);
for (int i=0;i<n;i++) c[i]=a[i];
for (int i=0;i<len;i++) rev[i]=(rev[i>>1]>>1)|((i&1)<<(bit-1));
NTT(c,len,1); NTT(b,len,1);
for (int i=0;i<len;i++) b[i]=1ll*(2-1ll*c[i]*b[i]%Mod+Mod)%Mod*b[i]%Mod;
NTT(b,len,-1); b.resize(n);
}
poly fr,gr,tmp,q,R,Q;
void PolyMod(int n,int m,poly &f,poly &g,poly &r){
fr.clear(); tmp.clear(); q.clear(); R.clear();
f.resize(n+1); fr.resize(n+1);
for (int i=0;i<=n;i++) fr[n-i]=f[i];
mult(n-m+1,n,gr,fr,q);
q.resize(n-m+1);
reverse(q.begin(),q.end());
mult(m+1,n-m+1,g,q,R);
for (int i=0;i<m;i++) r[i]=(f[i]-R[i]+Mod)%Mod;
r.resize(m);
}
int n,k; poly res,x;
int val[410000];
int main(){
InitG();
n=read(); k=read();
a.resize(k+1); res.resize(k+1); x.resize(k+1);
for (int i=1;i<=k;i++) a[k-i]=(Mod-read()%Mod)%Mod;
for (int i=0;i<=k-1;i++) val[i]=(read()%Mod+Mod)%Mod;
a[k]=res[0]=1;
x[1]=1;
gr.resize(k+1);
for (int i=0;i<=k;i++) gr[k-i]=a[i];
PolyInv(k+1,gr,tmp);
for (int i=0;i<=k;i++) gr[i]=tmp[i];
while (n){
if (n&1){
mult(k,k,res,x,res);
PolyMod(2*k+1,k,res,a,res);
}
mult(k,k,x,x,x);
PolyMod(2*k+1,k,x,a,x);
n>>=1;
}
int ans=0; res.resize(k);
for (int i=0;i<k;i++) ans=(ans+1ll*res[i]*val[i])%Mod;
printf("%d\n",ans);
return 0;
}
字符串
后缀自动机（SAM）
#include<bits/stdc++.h>
using namespace std;
const int S=1;
int z,n,cnt,sz[2100000],a[2100000],c[2100000],len[2100000];
int link[2100000],trans[2100000][27];
long long ans;
char s[1100000];
inline void add(int loc){
int c=s[loc]-'a',v=z;
z=++cnt; len[z]=loc;
for (;v&&!trans[v][c];v=link[v]) trans[v][c]=z;
if (!v) link[z]=S;
else{
int x=trans[v][c];
if (len[v]+1==len[x]) link[z]=x;
else
{
int y=++cnt; len[y]=len[v]+1;
for (int i=0;i<=26;i++) trans[y][i]=trans[x][i];
link[y]=link[x]; link[x]=y; link[z]=y;
for (;trans[v][c]==x;v=link[v]) trans[v][c]=y;
}
}
sz[z]=1;
}
void calc(){
for (int i=1;i<=cnt;i++) c[len[i]]++;
for (int i=1;i<=cnt;i++) c[i]+=c[i-1];
for (int i=1;i<=cnt;i++) a[c[len[i]]--]=i;
for (int i=cnt;i;i--){
int u=a[i];
sz[link[u]]+=sz[u];
ans+=1ll*(len[u]-len[link[u]])*sz[u]*(n-sz[u]);
}
}
int main(){
scanf("%s",s+1); n=strlen(s+1);
z=1; cnt=1;
for (int i=1;i<=n;i++) add(i);
calc();
printf("%lld\n",ans);
return 0;
}
回文自动机（PAM）
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
typedef long long ll;
const int MAXN=310000;
const int Mod=1e9+7;
const int inv2=5e8+4;
char s[MAXN];
class Palindromic_tree{
/*
两棵树，记录长度为奇数和偶数的回文串
0为长度为偶数的根,1为长度为奇数的根
*1. 偶数根节点字符长度为0，不存在，将它看做一个不在字符集中的字符-1
*2. 奇数根节点字符长度为-1，作用相当于backspace，方便处理单字符形成的回文串
*3. 只更改了最长的满足条件回文串的个数，
最后要从1->tot，把fail,fail[fail],...都也加上，这样显然会T
所以要倒过来，从tot->1，cnt[fail]+=cnt[now];
*/
private:
int now,tot,s[MAXN];
int fail[MAXN],cnt[MAXN],len[MAXN],ch[MAXN][26];
inline int newnode(int x){ //新建一个节点，长度为x
len[++tot]=x;
return tot;
}
inline int getfail(int x,int r){ //从l节点开始找s[r]的fail
while (s[r-len[x]-1]!=s[r]) x=fail[x]; //一直跳直到找到后缀回文
return x;
}
public:
void build(const char *t,int n){
for (int i=1;i<=n;i++) s[i]=t[i]-'a';
s[0]=-1; fail[0]=1; len[0]=0; //*1.
len[1]=-1; //*2.
now=0; tot=1; //当前在0号节点，用了<=1的位置
int x,y;
for (int i=1;i<=n;i++){
x=getfail(now,i); //找到回文的位置
if (!ch[x][s[i]]){ //没转移过
y=newnode(len[x]+2); //前后都加上这个字符，长度加2
fail[y]=ch[getfail(fail[x],i)][s[i]]; //记录新的fail
ch[x][s[i]]=y;
}
now=ch[x][s[i]]; cnt[now]++; //记录出现次数（只记录了最长的满足条件的）*3.
}
}
ll getans(){
ll res=0;
for (int i=tot;i>=1;i--){
cnt[fail[i]]+=cnt[i];
res=(res+1ll*cnt[i]*(cnt[i]-1)%Mod*inv2)%Mod;
}
return res;
}
} tree;
int main(){
scanf("%s",s+1);
tree.build(s,strlen(s+1));
printf("%lld\n",tree.getans());
return 0;
}
后缀数组（SA）
老的
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
char s[1100000];
int y[1100000],x[1100000],c[1100000],sa[1100000],rk[1100000],height[1100000],wt[30];
int n,m;
void get_SA(){
for (int i=1;i<=n;++i) ++c[x[i]=s[i]];
//c数组是桶
//x[i]是第i个元素的第一关键字
for (int i=2;i<=m;++i) c[i]+=c[i-1];
//做c的前缀和，我们就可以得出每个关键字最多是在第几名
for (int i=n;i>=1;--i) sa[c[x[i]]--]=i;
for (int k=1;k<=n;k<<=1){
int num=0;
for (int i=n-k+1;i<=n;++i) y[++num]=i;
//y[i]表示第二关键字排名为i的数，第一关键字的位置
//第n-k+1到第n位是没有第二关键字的 所以排名在最前面
for (int i=1;i<=n;++i) if (sa[i]>k) y[++num]=sa[i]-k;
//排名为i的数 在数组中是否在第k位以后
//如果满足(sa[i]>k) 那么它可以作为别人的第二关键字，就把它的第一关键字的位置添加进y就行了
//所以i枚举的是第二关键字的排名，第二关键字靠前的先入队
for (int i=1;i<=m;++i) c[i]=0;
//初始化c桶
for (int i=1;i<=n;++i) ++c[x[i]];
//因为上一次循环已经算出了这次的第一关键字 所以直接加就行了
for (int i=2;i<=m;++i) c[i]+=c[i-1];//第一关键字排名为1~i的数有多少个
for (int i=n;i>=1;--i) sa[c[x[y[i]]]--]=y[i],y[i]=0;
//因为y的顺序是按照第二关键字的顺序来排的
//第二关键字靠后的，在同一个第一关键字桶中排名越靠后
//基数排序
swap(x,y);
//这里不用想太多，因为要生成新的x时要用到旧的，就把旧的复制下来，没别的意思
x[sa[1]]=1;num=1;
for (int i=2;i<=n;++i)
x[sa[i]]=(y[sa[i]]==y[sa[i-1]] && y[sa[i]+k]==y[sa[i-1]+k]) ? num : ++num;
//因为sa[i]已经排好序了，所以可以按排名枚举，生成下一次的第一关键字
if (num==n) break;
m=num;
//这里就不用那个122了，因为都有新的编号了
}
for (int i=1;i<=n;++i) printf("%d ",sa[i]);
}
void get_height(){
int k=0;
for (int i=1;i<=n;++i) rk[sa[i]]=i;
for (int i=1;i<=n;++i){
if (rk[i]==1) continue;//第一名height为0
if (k) --k;//h[i]>=h[i-1]-1;
int j=sa[rk[i]-1];
while (j+k<=n && i+k<=n && s[i+k]==s[j+k]) ++k;
height[rk[i]]=k;//h[i]=height[rk[i]];
}
putchar(10);
for (int i=1;i<=n;++i) printf("%d ",height[i]);
}
int main(){
gets(s+1);
n=strlen(s+1); m=122;
//因为这个题不读入n和m所以要自己设
//n表示原字符串长度，m表示字符个数，ascll('z')=122
//我们第一次读入字符直接不用转化，按原来的ascll码来就可以了
//因为转化数字和大小写字母还得分类讨论，怪麻烦的
get_SA(); //get_height();
return 0;
}
新的
struct SA{
int f[N],g[N],a[N],h[N],val[20][N];
int sa[N],rk[N],oldrk[N];
void build(){
memset(f,0,sizeof(f)); int t;
for (int i=1;i<=n;i++) f[s[i]-'a'+1]=1;
for (int i=1;i<=26;i++) f[i]+=f[i-1]; t=f[26];
for (int i=1;i<=n;i++) rk[i]=f[s[i]-'a'+1];
for (int i=1;i<n;i<<=1){
for (int j=1;j<=n;j++) oldrk[j]=rk[j];
for (int j=1;j<=n;j++) a[j]=j+i<=n?rk[j+i]:0;//后i位的rank
memset(f,0,sizeof(f));
for (int j=1;j<=n;j++) f[a[j]]++;
for (int j=1;j<=t;j++) f[j]+=f[j-1];
for (int j=1;j<=n;j++) g[f[a[j]]--]=j;//以后i位的rank为关键字的排序结果
memset(f,0,sizeof(f));
for (int j=1;j<=n;j++) f[rk[j]]++;
for (int j=1;j<=t;j++) f[j]+=f[j-1];
for (int j=n;j>=1;j--) sa[f[rk[g[j]]]--]=g[j];//以前i位rank为第一关键字，后i位rank为第二关键字的排序结果
t=0;
for (int j=1;j<=n;j++){
t+=oldrk[sa[j]]>oldrk[sa[j-1]]||(oldrk[sa[j]]==oldrk[sa[j-1]]&&a[sa[j]]>a[sa[j-1]]);
rk[sa[j]]=t;
}
}
for (int j=1;j<=n;j++) sa[rk[j]]=j;
int j=0;
for (int i=1;i<=n;i++){
if (rk[i]==n) j=0;
else{
if (j) j--;
while (s[i+j]==s[sa[rk[i]+1]+j]) j++;
}
h[rk[i]]=j;
}
for (int i=1;i<=n;i++) val[0][i]=h[i];
for (int j=1;(1<<j)<=n;j++)
for (int i=1;i+(1<<j)-1<=n;i++)
val[j][i]=min(val[j-1][i],val[j-1][i+(1<<(j-1))]);
}
int lcp(int x,int y){
x=rk[x]; y=rk[y];
if (x>y) swap(x,y);
y--; int k=Log2[y-x+1];
return min(val[k][x],val[k][y-(1<<k)+1]);
}
};
Manacher
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int p[21000000];
char s[11000000];
char t[21000000];//存添加字符后的字符串
int init(){//形成新的字符串
int len=strlen(s);//len是输入字符串的长度
t[0]='$';//处理边界，防止越界
t[1]='#';
int j=2;
for (int i=0;i<len;i++){
t[j++]=s[i];
t[j++]='#';
}
t[j]='\0';//处理边界，防止越界（容易忘记）
return j;// 返回t的长度
}
int Manacher(){//返回最长回文串
int len=init();//取得新字符串的长度， 完成向t的转换
int max_len=-1;//最长回文长度
int id;
int mx=0;
for (int i=1;i<=len;i++){
if (i<mx)
p[i]=min(p[2*id-i],mx-i);//上面图片就是这里的讲解
else p[i]=1;
while (t[i-p[i]]==t[i+p[i]])//不需边界判断，因为左有'$'，右有'\0'标记；
p[i]++;//mx对此回文中点的贡献已经结束，现在是正常寻找扩大半径
if (mx<i+p[i]){//每走移动一个回文中点，都要和mx比较，使mx是最大，提高p[i]=min(p[2*id-i],mx-i)效率
id=i;//更新id
mx=i+p[i];//更新mx
}
max_len=max(max_len,p[i]-1);
}
return max_len;
}
int main(){
scanf("%s",s);
printf("%d",Manacher());
return 0;
}
0/1 可持久化 trie
void change(int &x,int dep,int v){
tree[++cnt]=tree[x]; x=cnt;
tree[x].sz++;
if (dep==-1) return;
bool k=v&(1<<dep);
if (k) change(tree[x].ch[1],dep-1,v);
else change(tree[x].ch[0],dep-1,v);
}
void build(){
cnt=0;
for (int i=1;i<=n;i++){
rt[i]=rt[i-1];
change(rt[i],30,a[i]);
}
}
离线可删线性基
#include<cstdio>
#include<algorithm>
#include<unordered_map>
using namespace std;
int n,m,Q,ans,sz,op[2100000],x[2100000],lst[2100000],nxt[2100000];
bool vis[35];
struct node{
int x,y;
bool operator>(const node &a) const{
return nxt[y]>nxt[a.y];
}
} c[35];
char Getchar(){
static char now[1<<20],*S,*T;
if (T==S){
T=(S=now)+fread(now,1,1<<20,stdin);
if (T==S) return EOF;
}
return *S++;
}
int read(){
int x=0,f=1;
char ch=Getchar();
while (ch<'0'||ch>'9'){
if (ch=='-') f=-1;
ch=Getchar();
}
while (ch<='9'&&ch>='0') x=x*10+ch-'0',ch=Getchar();
return x*f;
}
unordered_map<int,int> num;
void ins(node x){
for (int i=n;i>=0;i--)
if (x.x&(1<<i)){
if (!vis[i]){
vis[i]=true; sz++;
c[i]=x; break;
} else{
if (x>c[i]) swap(c[i],x);
x.x^=c[i].x;
}
}
}
void del(int x){
for (int i=n;i>=0;i--)
if (vis[i]&&c[i].y==x){
vis[i]=false; sz--;
break;
}
}
int main(){
n=read(); Q=read(); m=(1<<n);
for (int i=1;i<=Q;i++){
op[i]=read(); x[i]=read();
nxt[num[x[i]]]=i; lst[i]=num[x[i]];
num[x[i]]=i;
}
for (int i=1;i<=Q;i++)
if (!nxt[i]) nxt[i]=Q+1;
for (int i=1;i<=Q;i++){
if (op[i]==1) ins((node){x[i],i});
else del(lst[i]);
ans^=(m/(1<<sz));
}
printf("%d\n",ans);
return 0;
}
AC 自动机
#include<cstdio>
#include<cstring>
using namespace std;
int T,n,q,a[510000],pos[510000],len[510000],l[510000];
int tot,sum[510000],fail[510000],ch[510000][27];
int head,tail,que[510000];
char st[510000],s[510000],pre[510000],suf[510000];
int ins(){
int now=0,len;
len=strlen(suf);
for (int i=0;i<len;i++){
if (!ch[now][suf[i]-'a']) ch[now][suf[i]-'a']=++tot;
now=ch[now][suf[i]-'a'];
}
if (!ch[now][26]) ch[now][26]=++tot;
now=ch[now][26];
len=strlen(pre);
for (int i=0;i<len;i++){
if (!ch[now][pre[i]-'a']) ch[now][pre[i]-'a']=++tot;
now=ch[now][pre[i]-'a'];
}
l[now]=strlen(suf)+strlen(pre);
return now;
}
void build(){
int head=1,tail=0;
for (int i=0;i<=26;i++)
if (ch[0][i]) que[++tail]=ch[0][i];
while (head<=tail){
int now=que[head++];
for(int i=0;i<=26;i++){
if (ch[now][i]){
fail[ch[now][i]]=ch[fail[now]][i];
que[++tail]=ch[now][i];
}
else ch[now][i]=ch[fail[now]][i];
}
}
}
void query(int x,int len){
int now=0;
for (int i=x+1;i<=x+len;i++) now=ch[now][st[i]-'a'];
now=ch[now][26];
for (int i=x+1;i<=x+len;i++){
now=ch[now][st[i]-'a'];
int tmp=now;
while (l[tmp]>len) tmp=fail[tmp];
sum[tmp]++;
}
}
int main(){
scanf("%d",&T);
while (T--){
memset(fail,0,sizeof(fail));
memset(sum,0,sizeof(sum));
memset(ch,0,sizeof(ch));
scanf("%d%d",&n,&q);
int cnt=0; tot=0;
for (int i=1;i<=n;i++){
scanf("%s",s+1); len[i]=strlen(s+1);
a[i]=cnt;
for (int j=1;j<=len[i];j++) st[++cnt]=s[j];
}
for (int i=1;i<=q;i++){
scanf("%s%s",pre,suf);
pos[i]=ins();
}
build();
for (int i=1;i<=n;i++) query(a[i],len[i]);
for (int i=tot;i>=1;i--) sum[fail[que[i]]]+=sum[que[i]];
for (int i=1;i<=q;i++) printf("%d\n",sum[pos[i]]);
}
return 0;
}
分治
整体二分
#include<cstdio>
#include<vector>
using namespace std;
const int MAXN=1100000;
typedef long long ll;
int n,m,x,k,t[MAXN],ans[MAXN];
ll tree[MAXN];
vector<int> vec[MAXN];
struct node{
int l,r,num;
bool isq;
ll k;
} a[MAXN],Left[MAXN],Right[MAXN];
inline void add(int x,ll y){
for (;x<=m;x+=x&-x) tree[x]+=y;
}
inline ll getsum(int x){
ll sum=0;
for (;x;x-=x&-x) sum+=tree[x];
return sum;
}
void solve(int L,int R,int l,int r){
if (l>r) return;
if (L==R){
for (int i=l;i<=r;i++)
if (a[i].isq) ans[a[i].num]=L;
return;
}
int mid=(L+R)>>1,n=0,m=0;
for (int i=l;i<=r;i++){
if (a[i].isq){
ll tmp=0;
for (int j=0;j<vec[a[i].num].size();j++){
tmp+=getsum(vec[a[i].num][j]);
if (tmp>=a[i].k) break;
}
if (tmp>=a[i].k) Left[++n]=a[i];
else a[i].k-=tmp,Right[++m]=a[i];
}
else{
if (a[i].num<=mid){
if (a[i].l<=a[i].r){
add(a[i].l,a[i].k);
add(a[i].r+1,-a[i].k);
}
else{
add(1,a[i].k);
add(a[i].r+1,-a[i].k);
add(a[i].l,a[i].k);
}
Left[++n]=a[i];
}
else Right[++m]=a[i];
}
}
for (int i=l;i<=r;i++)
if (a[i].num<=mid&&!a[i].isq){
if (a[i].l<=a[i].r){
add(a[i].l,-a[i].k);
add(a[i].r+1,a[i].k);
}
else{
add(1,-a[i].k);
add(a[i].r+1,a[i].k);
add(a[i].l,-a[i].k);
}
}
for (int i=1;i<=n;i++) a[l+i-1]=Left[i];
for (int i=1;i<=m;i++) a[l+n+i-1]=Right[i];
solve(L,mid,l,l+n-1); solve(mid+1,R,l+n,r);
}
int main(){
scanf("%d%d",&n,&m);
for (int i=1;i<=m;i++){
scanf("%d",&x);
vec[x].push_back(i);
}
for (int i=1;i<=n;i++) scanf("%d",&t[i]);
scanf("%d",&k);
for (int i=1;i<=k;i++){
scanf("%d%d%lld",&a[i].l,&a[i].r,&a[i].k);
a[i].isq=false; a[i].num=i;
}
for (int i=1;i<=n;i++){
a[i+k].k=t[i]; a[i+k].isq=true;
a[i+k].num=i;
}
solve(1,k+1,1,k+n);
for (int i=1;i<=n;i++)
if (ans[i]!=k+1) printf("%d\n",ans[i]);
else puts("NIE");
return 0;
}
CDQ 分治（三维偏序）
#include<cstdio>
#include<algorithm>
using namespace std;
const int MAXN=110000;
const int MAXM=210000;
struct node{
int s,c,m,num,tot;
} t[MAXN],a[MAXN];
int n,k,cnt,tree[MAXM],tot[MAXN],num[MAXN],ans[MAXN];
inline void add(int x,int y){
for (;x<=k;x+=x&(-x)) tree[x]+=y;
}
inline int getsum(int x){
int sum=0;
for (;x;x-=x&(-x)) sum+=tree[x];
return sum;
}
inline int cmp1(node a,node b){
return (a.s<b.s)||(a.s==b.s&&a.c<b.c)||(a.s==b.s&&a.c==b.c&&a.m<b.m);
}
inline int cmp2(node a,node b){
return (a.c<b.c)||(a.c==b.c&&a.m<b.m);
}
void CDQ(int l,int r){
if (l==r){
tot[a[l].num]+=a[l].tot-1;
return;
}
int mid=(l+r)>>1;
CDQ(l,mid); CDQ(mid+1,r);
sort(a+l,a+mid+1,cmp2); sort(a+mid+1,a+r+1,cmp2);
int i,j;
for (i=l,j=mid+1;j<=r;j++){
for (;i<=mid&&a[i].c<=a[j].c;i++) add(a[i].m,a[i].tot);
tot[a[j].num]+=getsum(a[j].m);
}
while ((--i)>=l) add(a[i].m,-a[i].tot);
}
int main(){
scanf("%d%d",&n,&k);
for (int i=1;i<=n;i++) scanf("%d%d%d",&t[i].s,&t[i].c,&t[i].m);
sort(t+1,t+n+1,cmp1);
for (int i=1;i<=n;i++)
if (i==1||t[i-1].s!=t[i].s||t[i-1].m!=t[i].m||t[i-1].c!=t[i].c){
a[++cnt]=t[i];
a[cnt].tot=1;
a[cnt].num=cnt;
} else a[cnt].tot++;
for (int i=1;i<=cnt;i++) num[i]=a[i].tot;
CDQ(1,cnt);
for (int i=1;i<=cnt;i++) ans[tot[i]]+=num[i];
for (int i=0;i<n;i++) printf("%d\n",ans[i]);
return 0;
}
计算几何
struct Point{
double x,y;
Point(double x=0,double y=0):x(x),y(y){}
};
typedef Point Vector;
Vector operator+(Vector A,Vector B){ return Vector(A.x+B.x,A.y+B.y);}
Vector operator-(Point A,Point B){ return Vector(A.x-B.x,A.y-B.y);}
Vector operator*(Vector A,double p){ return Vector(A.x*p,A.y*p);}
Vector operator/(Vector A,double p){ return Vector(A.x/p,A.y/p);}
const double eps=1e-6;
int sgn(double x){
if (fabs(x)<eps) return 0;
if (x<0) return -1;
return 1;
}
bool operator==(const Point& a,const Point& b){
if (sgn(a.x-b.x)==0&&sgn(a.y-b.y)==0) return true;
return false;
}
double Dot(Vector A,Vector B){ return A.x*B.x+A.y*B.y;}
double Length(Vector A){ return sqrt(Dot(A, A));}
double Angle(Vector A,Vector B){ return acos(Dot(A,B)/Length(A)/Length(B));}
double Cross(Vector A,Vector B){ return A.x*B.y-A.y*B.x;}
double Area(Point A,Point B,Point C){//计算两向量构成的三角形形有向面积
return Cross(B-A,C-A)/2;
}
double Area2(Point A,Point B,Point C){//计算两向量构成的平行四边形有向面积
return Cross(B-A,C-A);
}
Vector Rotate(Vector A,double rad){//rad为弧度 且为逆时针旋转的角
return Vector(A.x*cos(rad)-A.y*sin(rad),A.x*sin(rad)+A.y*cos(rad));
}
Vector Normal(Vector A){//向量A左转90°的单位法向量
double L=Length(A);
return Vector(-A.y/L,A.x/L);
}
bool ToLeftTest(Point a,Point b,Point c){ return Cross(b-a,c-b)>0;}
double DistanceToLine(Point P,Point A,Point B){//点P到直线AB距离公式
Vector v1=B-A,v2=P-A;
return fabs(Cross(v1,v2)/Length(v1));//不去绝对值，得到的是有向距离
}
double DistanceToSegment(Point P,Point A,Point B){//点P到线段AB距离公式
if (A==B) return Length(P-A);
Vector v1=B-A,v2=P-A,v3=P-B;
if (dcmp(Dot(v1,v2))<0) return Length(v2);
if (dcmp(Dot(v1,v3))>0) return Length(v3);
return DistanceToLine(P,A,B);
}
矩阵
cpp
struct matrix{
int v[55][55];
matrix(){ memset(v,0,sizeof(v));}
int det(){
int res=1;
for (int i=1;i<=K;i++){
if (!v[i][i]){
for (int j=i+1;j<=K;j++)
if (v[j][i]){ swap(v[i],v[j]); break;}
res=dec(0,res);
if (!v[i][i]) return 0;
}
ll inv=getinv(v[i][i]);
for (int j=i+1;j<=K;j++){
int tmp=mul(v[j][i],inv);
for (int k=i;k<=K;k++) v[j][k]=dec(v[j][k],mul(tmp,v[i][k]));
}
}
for (int i=1;i<=K;i++) res=mul(res,v[i][i]);
return res;
}
friend matrix operator+(const matrix &a,const matrix &b){
matrix res;
for (int i=1;i<=K;i++)
for (int j=1;j<=K;j++)
res.v[i][j]=add(a.v[i][j],b.v[i][j]);
return res;
}
friend matrix operator-(const matrix &a,const matrix &b){
matrix res;
for (int i=1;i<=K;i++)
for (int j=1;j<=K;j++)
res.v[i][j]=dec(a.v[i][j],b.v[i][j]);
return res;
}
friend matrix operator*(const matrix &a,const int b){
matrix res;
for (int i=1;i<=K;i++)
for (int j=1;j<=K;j++)
res.v[i][j]=mul(a.v[i][j],b);
return res;
}
friend matrix operator*(const matrix &a,const matrix &b){
matrix res;
for (int i=1;i<=K;i++)
for (int k=1;k<=K;k++)
if (a.v[i][k])
for (int j=1;j<=K;j++)
res.v[i][j]=add(res.v[i][j],mul(a.v[i][k],b.v[k][j]));
return res;
}
friend matrix operator^(matrix x,int a){
matrix res;
for (int i=1;i<=K;i++) res.v[i][i]=1;
while (a){
if (a&1) res=res*x;
x=x*x; a>>=1;
}
return res;
}
};
test