Submission #1117784

#	Time	Username	Problem	Language	Result	Execution time	Memory
1117784		vjudge1	Paprike (COI18_paprike)	C++17	24 / 100	71 ms	8216 KiB

paprike

#include "bits/stdc++.h"

using ll = long long;
using namespace std;

const int mxN = 100005;

vector<pair<int,int>> aj[mxN]; 
int cut[mxN];
ll a[mxN];
int flag = 0;
ll K;
int f;

int dfs(int u, int p = 0) {
    int sm = a[u - 1];
    for (auto [v, i] : aj[u]) {
        if (v ^ p) {
            int r = dfs(v, u);
            if (!cut[i]) {
                sm += r;
            }
        }
    }
    if (sm > K) {
        f = 0;
    }
    return sm;
}

int main() {
    int N;
    cin >> N >> K;
    for (int i = 0; i < N; i ++) {
        cin >> a[i];
    }
    vector<pair<int,int>> eg;

    for (int i = 0; i < N - 1; i ++) {
        int X, Y;
        cin >> X >> Y;
        eg.emplace_back(X, Y);
        aj[X].emplace_back(Y, i);
        aj[Y].emplace_back(X, i);
    }
    if (N <= 15) {
        int mn = INT_MAX;
        for (int i = 0; i < (1 << (N - 1)); i ++) {
            for (int j = 0; j < N - 1; j ++) {
                int bt = (i >> j) & 1;
                if (bt) {
                    cut[j] = 1;
                }
            }
            f = 1;
            dfs(1);
            if (f) {
                mn = min(mn, __builtin_popcount(i));
            }
            for (int j = 0; j < N - 1; j ++) {
                cut[j] = 0;
            }
        }
        cout << mn << endl;
    } else {
        vector<int> b(N + 1);
        for (int i = 1; i <= N; i ++) {
            b[i] = a[i - 1];
        }
        for (int i = 1; i <= N; i ++) {
            a[i] = b[i];
        }
        int cnt = 0;
        int j = 0;
        for (int i = 0; i < N;) {
            ll sm = 0;
            for (; i < N && sm + a[i + 1] <= K; i ++) {
                sm += a[i + 1];
            }
            if (i != N) {
                cnt ++;
            }
        }
        cout << cnt << endl;
    }
}

Compilation message (stderr)

paprike.cpp: In function 'int main()':
paprike.cpp:74:13: warning: unused variable 'j' [-Wunused-variable]
   74 |         int j = 0;
      |             ^

• Subtask 1: 11 / 11
• Subtask 2: 13 / 13
• Subtask 3: 0 / 27
• Subtask 4: 0 / 49