Laskettelukeskus

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

ll n, in1, in2, s;
vector<vector<ll>> v;
vector<ll> c;
vector<ll> z;
vector<ll> a;

void f(int x){

    if (z[x]) return;
    z[x] = 1;

    for (auto u : v[x]){
        a.push_back(x);
        f(u);
        a.pop_back();
    }

    if (c[x]){
        for (auto u : a){
            if (c[u]-c[x] > 0) c[u] -= c[x];
            else c[u] = 0;
        }
        s += c[x];
        c[x] = 0;
    }
}

int main(){

cin >> n;
v.resize(n+1, vector<ll> (0)); 
z.resize(n+1, 0);

for(int i = 0; i < n-1; i++){
    cin >> in1 >> in2;
    v[in1].push_back(in2);
}

c.push_back(0);
for (int i = 0; i < n; i++){
    cin >> in1;
    c.push_back(in1);
}

s = 0;

f(1);

cout << s;

}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 1, 2

Verdict: ACCEPTED

Test 3

Group: 1, 2

Verdict: ACCEPTED

Test 4

Group: 2

Verdict: ACCEPTED

Test 5

Group: 2

Verdict: ACCEPTED

Test 6

Group: 1, 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 1, 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 1, 2

Verdict: ACCEPTED

Test 11

Group: 2

Verdict: ACCEPTED

Test 12

Group: 1, 2

Verdict: ACCEPTED

Test 13

Group: 2

Verdict: ACCEPTED