Submission #286816

---

Source Code Expand

#include <iostream>
#include <vector>
#include <queue>
#include <string>
#include <cstring>
#include <cstdio>
#include <sstream>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <set>
#include <map>
#include <list>
#include <iomanip>

#define INF 1000000001
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define RFOR(i, a, b) for (int i = (a); i >= (b); i--)

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
const double PI = acos(-1.0);

int N, X;
int h[101];
int a[101], b[101];
vector<int> G[101];

int dfs(int x, int par)
{
	int res=0;
	bool isleaf=true;

	FOR(i,0,G[x].size()) {
		if (G[x][i]!=par) {
			isleaf = false;
			res += dfs(G[x][i], x);
		}
	}
	if (isleaf) {
		if (h[x] > 0) res += 2;
	} else {
		if (res > 0 && par >= 0) {
			res += 2;
		}
	}

	return res;	
}

int main()
{
	ios::sync_with_stdio(false);

	cin >> N >> X;
	X--;
	FOR(i,0,N) cin >> h[i];
	FOR(i,0,N-1) {
		cin >> a[i] >> b[i];
		a[i]--, b[i]--;
	}
	FOR(i,0,N-1) {
		G[a[i]].push_back(b[i]);
		G[b[i]].push_back(a[i]);
	}

	printf("%d\n", dfs(X, -1));


	return 0;
}

Submission Info

Judge Result