Submission #1564962

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Source Code Expand

#include<bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
  int n,m;
  cin>>n>>m;
  vector<int> G[n];
  for(int i=0;i<m;i++){
    int a,b;
    cin>>a>>b;
    a--;b--;
    G[b].push_back(a);
  }
  int used[n];
  memset(used,0,sizeof(used));
  queue<int> q;
  q.push(0);
  while(!q.empty()){
    int p=q.front();q.pop();
    if(used[p]) continue;
    used[p]=1;
    for(int u:G[p]) q.push(u);
  }
  int x=0;
  for(int i=0;i<n;i++) x+=used[i];
  cout<<x<<endl;
  return 0;
}

Submission Info

Judge Result