tarjan缩点

整理了下模板。。。

#include<iostream>
#include<cstdio>
#include<cmath>
#include<algorithm>
#include<queue>
#include<cstring>
#define PAU putchar(' ')
#define ENT putchar('
')
using namespace std;
const int maxn=100000+10,maxm=500000+10;
int low[maxn],dfn[maxn],s[maxn],beg[maxn],top,scc,cz;bool ins[maxn];
struct ted{int x,y;ted*nxt;}adj[maxm],*fch[maxn],*ms=adj;
void add(int x,int y){*ms=(ted){x,y,fch[x]};fch[x]=ms++;return;}
void tarjan(int u){
    low[u]=dfn[u]=++cz;ins[u]=true;s[++top]=u;
    for(ted*e=fch[u];e;e=e->nxt){
        int v=e->y;if(!dfn[v])tarjan(v),low[u]=min(low[u],low[v]);
        else if(ins[v])low[u]=min(low[u],dfn[v]);
    }if(low[u]==dfn[u]){
        scc++;int t=-1;while(t!=u)beg[t=s[top--]]=scc,ins[t]=false;
    }return;
}
inline int read(){
    int x=0,sig=1;char ch=getchar();
    while(!isdigit(ch)){if(ch=='-')sig=-1;ch=getchar();}
    while(isdigit(ch))x=10*x+ch-'0',ch=getchar();
    return x*=sig;
}
inline void write(int x){
    if(x==0){putchar('0');return;}if(x<0)putchar('-'),x=-x;
    int len=0,buf[15];while(x)buf[len++]=x%10,x/=10;
    for(int i=len-1;i>=0;i--)putchar(buf[i]+'0');return;
}
int n,m;
void init(){
    n=read();m=read();int x,y;
    while(m--){x=read();y=read();add(x,y);}
    for(int i=1;i<=n;i++) if(!dfn[i]) tarjan(i);
    for(int i=1;i<=n;i++){
        printf("%d:%d
",i,beg[i]);
    }
    return;
}
void work(){
    return;
}
void print(){
    return;
}
int main(){init();work();print();return 0;}
/*
5 5
1 2
2 3
3 4
4 5
5 1
*/