Submission #286594

---

Source Code Expand

#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <ctime>
#include <cassert>
#include <string>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <functional>
#include <iostream>
#include <map>
#include <set>
using namespace std;
typedef pair<int,int> P;
typedef pair<int,P> P1;
typedef pair<P,P> P2;
typedef long long ll;
#define pu push
#define pb push_back
#define mp make_pair
#define eps 1e-7
#define INF 1000000000
#define fi first
#define sc second
#define rep(i,x) for(int i=0;i<x;i++)
int sub[105];
int e[105];
vector<int>edge[105];
int res = 0;
void dfs(int v,int u)
{
	sub[v] = e[v];
	for(int i=0;i<edge[v].size();i++)
	{
		if(edge[v][i] == u) continue;
		dfs(edge[v][i],v);
		sub[v] += sub[edge[v][i]];
	}
}
void d(int v,int u)
{
	for(int i=0;i<edge[v].size();i++)
	{
		if(edge[v][i] == u) continue;
		if(sub[edge[v][i]])
		{
			res++;
			d(edge[v][i],v);
		}
	}
}
int main()
{
	int n,x;
	cin >> n >> x;
	for(int i=1;i<=n;i++) cin >> e[i];
	for(int i=1;i<n;i++)
	{
		int a,b; cin >> a >> b;
		edge[a].pb(b);
		edge[b].pb(a);
	}
	dfs(x,-1);
	d(x,-1);
	cout << res*2 << endl;
}

Submission Info

Judge Result