Laskettelukeskus

#include <ios>
#include <iostream>
#include <vector>

int main() {
    std::ios_base::sync_with_stdio(0);
    std::cin.tie(0);

    long rinteet;
    std::cin >> rinteet;

    std::vector<std::pair<long, long>> paths;
    paths.reserve(rinteet);
    std::vector<std::pair<long, long>> huiput;
    huiput.reserve(rinteet);
    huiput.push_back(std::pair(0, 0));

    for (long i = 0; i < rinteet-1; ++i) {
        long n1;
        long n2;

        std::cin >> n1 >> n2;

        paths.push_back(std::pair(n2, n1));
    }

    for (long i = 0; i < rinteet; ++i) {
        long n;
        std::cin >> n;

        huiput.push_back(std::pair(n, 0));
    }

    for (auto path : paths) {
        long idx = path.second;

        long value = std::max(huiput[path.first].first, huiput[path.first].second);

        while (huiput[idx].second < 0) {
            long capacity = huiput[idx].first;
            huiput[idx].first = std::max(0l, capacity-value);

            value = std::max(0l, value-capacity);

            idx = std::abs(huiput[idx].second);
        }

        huiput[idx].second += value;
        huiput[path.first].first -= huiput[path.first].second;
        huiput[path.first].second = -path.second;
    }

    std::cout << std::max(huiput[1].second, huiput[1].first);
}

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: TIME LIMIT EXCEEDED

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