Submission #1574092


Source Code Expand

#include<bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;

const int MAX = 2e5+1;

bool ok = true;
vector<vector<int>> g;
vector<ll> a;

ll go(int u, int p) {
    ll sum = 0;
    bool leaf = true;
    vector<ll> d(g[u].size());
    for(int i = 0; i < g[u].size(); i++) {
        int v = g[u][i];
        if(v != p) {
            leaf = false;
            d[i] = go(v, u);
            sum += d[i];
        }
    }
//    cout << u << " - " << sum << endl;
    if(leaf || (p == -1 && g[u].size() == 1)) {
        if(p == -1) ok &= sum == a[u];
        return a[u];
    }
    ll r = 2*a[u] - sum;
//    cout << u << " " << r << " " << sum << endl;
    if(p != -1) ok &= r >= 0;
    if(p != -1) sum += r;
    ok &= sum == 2*a[u];
    ok &= sum % 2 == 0;
    for(int i = 0; i < g[u].size(); i++) {
        ok &= d[i] <= sum/2;
    }
    ok &= r <= sum/2;
    return r;
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    #ifdef LOCAL
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #else
        #define endl '\n'
    #endif

    int n; cin >> n;
    g.assign(n+1, vector<int>());
    a.assign(n+1, 0);

    for(int i = 1; i <= n; i++) {
        cin >> a[i];
    }

    for(int i = 1; i < n; i++) {
        int a, b; cin >> a >> b;
        g[a].push_back(b);
        g[b].push_back(a);
    }

    go(1, -1);

    if(ok) cout << "YES" << endl;
    else cout << "NO" << endl;

}

Submission Info

Submission Time
Task C - Cleaning
User vjudge5
Language C++14 (GCC 5.4.1)
Score 700
Code Size 1491 Byte
Status AC
Exec Time 70 ms
Memory 15872 KB

Judge Result

Set Name Sample All
Score / Max Score 0 / 0 700 / 700
Status
AC × 3
AC × 51
Set Name Test Cases
Sample sample1.txt, sample2.txt, sample3.txt
All sample1.txt, sample2.txt, sample3.txt, in1.txt, in10.txt, in11.txt, in12.txt, in13.txt, in14.txt, in15.txt, in16.txt, in17.txt, in18.txt, in19.txt, in2.txt, in20.txt, in21.txt, in22.txt, in23.txt, in24.txt, in25.txt, in26.txt, in27.txt, in28.txt, in29.txt, in3.txt, in30.txt, in31.txt, in32.txt, in33.txt, in34.txt, in35.txt, in36.txt, in37.txt, in38.txt, in39.txt, in4.txt, in40.txt, in41.txt, in42.txt, in43.txt, in44.txt, in45.txt, in5.txt, in6.txt, in7.txt, in8.txt, in9.txt, sample1.txt, sample2.txt, sample3.txt
Case Name Status Exec Time Memory
in1.txt AC 49 ms 6656 KB
in10.txt AC 53 ms 6656 KB
in11.txt AC 54 ms 14080 KB
in12.txt AC 51 ms 14080 KB
in13.txt AC 49 ms 15872 KB
in14.txt AC 47 ms 14592 KB
in15.txt AC 1 ms 256 KB
in16.txt AC 1 ms 256 KB
in17.txt AC 1 ms 256 KB
in18.txt AC 1 ms 256 KB
in19.txt AC 48 ms 6656 KB
in2.txt AC 47 ms 6656 KB
in20.txt AC 48 ms 6656 KB
in21.txt AC 48 ms 6656 KB
in22.txt AC 48 ms 6656 KB
in23.txt AC 47 ms 6656 KB
in24.txt AC 62 ms 6656 KB
in25.txt AC 1 ms 256 KB
in26.txt AC 49 ms 6656 KB
in27.txt AC 49 ms 6656 KB
in28.txt AC 1 ms 256 KB
in29.txt AC 44 ms 6656 KB
in3.txt AC 45 ms 6656 KB
in30.txt AC 1 ms 256 KB
in31.txt AC 49 ms 6656 KB
in32.txt AC 47 ms 6656 KB
in33.txt AC 48 ms 6656 KB
in34.txt AC 47 ms 6656 KB
in35.txt AC 49 ms 6656 KB
in36.txt AC 47 ms 6656 KB
in37.txt AC 2 ms 384 KB
in38.txt AC 70 ms 6656 KB
in39.txt AC 45 ms 6656 KB
in4.txt AC 49 ms 6656 KB
in40.txt AC 45 ms 6656 KB
in41.txt AC 48 ms 6656 KB
in42.txt AC 61 ms 6656 KB
in43.txt AC 47 ms 6656 KB
in44.txt AC 48 ms 6656 KB
in45.txt AC 48 ms 6656 KB
in5.txt AC 47 ms 6656 KB
in6.txt AC 50 ms 6656 KB
in7.txt AC 44 ms 5888 KB
in8.txt AC 12 ms 1792 KB
in9.txt AC 48 ms 6656 KB
sample1.txt AC 1 ms 256 KB
sample2.txt AC 1 ms 256 KB
sample3.txt AC 1 ms 256 KB