Submission #3188086

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Source Code Expand

#include<iostream>
#include<vector>
using namespace std;
#define rep(i,n) for(int i = 1; i <= n; i++)
#define MAX_N 108

int n, X, a, b;
bool h[MAX_N], used[MAX_N];
vector<int> G[MAX_N];

int dfs(int x){
	int ans = 0;
	used[x] = true;
	
	for(int y : G[x]){
		if(used[y]) continue;
		ans += dfs(y);
	}
	
	if((ans||h[x])&&x!=X) ans += 2;
	
	return ans;
}

int main(){

	cin>>n>>X;
	
	rep(i,n) cin>>h[i];
	
	rep(i,n-1){
		cin>>a>>b; 
		G[a].push_back(b),G[b].push_back(a);
	}
	
	cout<<dfs(X)<<endl;
	
	return 0;
}

Submission Info

Judge Result