Submission #1359064

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Source Code Expand

#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <functional>
#include <stack>
using namespace std;
int N,x;
int a[101];
vector<int> G[101];
int ans;
int dfs(int v,int pre){
  for(int i=0;i<G[v].size();i++){
    int u=G[v][i];
    if(u==pre)continue;
    if(dfs(u,v)){
      ans++;
      a[v]=1;
    }
  }
  if(a[v]==1)return true;
}
int main(){
  cin >> N >> x;
  x--;
  for(int i=0;i<N;i++)cin >> a[i];
  for(int i=0;i<N-1;i++){
    int s,t;
    cin >> s >> t;
    s--;t--;
    G[s].push_back(t);
    G[t].push_back(s);
  }

  dfs(x,-1);
  cout << 2*ans << endl;
  return 0;
}

Submission Info

Judge Result