Laskettelukeskus

#include <bits/stdc++.h>

using namespace std;

class Slope
{
public:
    long long id;
    long long plowsNeeded;
    vector<long long> children;

    Slope(long long _id, long long _plowsNeeded) : id(_id), plowsNeeded(_plowsNeeded) {}
};

long long minSnowplows(vector<Slope> &slopes, long long currentSlope)
{
    long long totalPlows = 0;

    for (long long child : slopes[currentSlope].children)
    {
        totalPlows += minSnowplows(slopes, child);
    }

    long long additionalPlows = max<long long>(0, slopes[currentSlope].plowsNeeded - totalPlows);
    totalPlows += additionalPlows;

    return totalPlows;
}

int main()
{
    long long n;
    cin >> n;

    vector<Slope> slopes(n + 1, Slope(0, 0)); 

    for (long long i = 1; i < n; ++i)
    {
        long long a, b;
        cin >> a >> b;
        slopes[a].children.push_back(b);
        slopes[b].id = b;
    }

    for (long long i = 1; i <= n; ++i)
    {
        cin >> slopes[i].plowsNeeded;
    }

    long long result = minSnowplows(slopes, 1); 
    cout << result << endl;

    return 0;
}

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