算法1

#include <iostream>  //直接暴力dfs即可
#include <cstring>
#include <algorithm>
#include <bitset>
using namespace std;
const int N = 2e5+10;
bool ver[N];
int h[N],ne[N],e[N],idx;
bitset<30010> cnt[N];
int n,m;
void add(int a,int b){
    e[idx] = b,ne[idx] = h[a],h[a] = idx ++;
}
void dfs(int u){   
    if(ver[u]) return ;
    ver[u] = true;
    cnt[u][u] = 1;
    for(int i = h[u];~i;i = ne[i]){
        int j = e[i];
    //    if(ver[j]) continue;
        dfs(j);
        cnt[u] |= cnt[j];
    }
}
int main()
{
    cin >> n >> m;
    int root = 0x3f3f3f3f;
    memset(h,-1,sizeof h);
    for(int i = 0;i<m;i++){
        int a,b; cin >> a >> b;
        add(a,b);
    }

    for(int i = 1;i<=n;i++) dfs(i);
    for(int i = 1;i<=n;i++) cout << cnt[i].count() << endl;
    return 0;
}