Submission #1368202

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<double, double> pdd;
typedef vector<int> vec;
typedef vector<vec> graph;
const ull mod = 1e9 + 7;
#define REP(i,n) for(int i=0;i<(int)n;++i)
bool checked[105];
graph g(105);
int tr[105];

int dfs(int x){
    if(checked[x]) return 0;
    checked[x] = true;
    int dist = 0;
    REP(i, g[x].size()){
        dist+=dfs(g[x][i]);
    }
    if(dist==0){
        if(tr[x]==1){
            dist = 2;
        }
    }else{
        dist+=2;
    }
    return dist;
}

int main(){
    int n, x;
    cin >> n >> x;
    x--;
    REP(i, n) cin >> tr[i];
    REP(i, n-1){
        int s, t;
        cin >> s >> t;
        s--;
        t--;
        g[s].push_back(t);
        g[t].push_back(s);
    }
    REP(i, n) checked[i] = false;
    cout << dfs(x)-2 << endl;
    return 0;
}

Submission Info

Judge Result