Submission #1264582

#	Time	Username	Problem	Language	Result	Execution time	Memory
1264582		podvorniy	Table Tennis (info1cup20_tabletennis)	C++20	100 / 100	127 ms	11704 KiB

tabletennis

#include <iostream>
#include <vector>
#include <algorithm>
#include <set>

using namespace std;

typedef long long ll;

bool check(ll S, const vector<ll>& a, int N, int K, int M) {
    int total = a.size();
    int left = 0, right = total - 1;
    int skips = 0;
    int pairs = 0;
    while (left < right && pairs < M && skips <= K) {
        if (a[left] + a[right] == S) {
            pairs++;
            left++;
            right--;
        } else if (a[left] + a[right] < S) {
            skips++;
            left++;
        } else {
            skips++;
            right--;
        }
    }
    if (skips > K) return false;
    if (pairs < M) {
        if (left == right) {
            skips++;
        }
        if (skips > K) return false;
        return pairs == M;
    }
    skips += (right - left + 1);
    return skips == K;
}

vector<ll> build_solution(ll S, const vector<ll>& a, int N, int K) {
    int total = a.size();
    int left = 0, right = total - 1;
    vector<ll> taken;
    while (left <= right && taken.size() < N) {
        if (a[left] + a[right] == S) {
            taken.push_back(a[left]);
            taken.push_back(a[right]);
            left++;
            right--;
        } else if (a[left] + a[right] < S) {
            left++;
        } else {
            right--;
        }
    }
    sort(taken.begin(), taken.end());
    return taken;
}

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

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

    sort(a.begin(), a.end());

    int M = N / 2;

    set<ll> candidates;
    for (int i = 0; i <= K; i++) {
        for (int j = total - 1; j >= total - 1 - K; j--) {
            candidates.insert(a[i] + a[j]);
        }
    }

    for (ll S : candidates) {
        if (check(S, a, N, K, M)) {
            vector<ll> sol = build_solution(S, a, N, K);
            for (size_t i = 0; i < sol.size(); i++) {
                cout << sol[i];
                if (i < sol.size() - 1) cout << " ";
            }
            cout << endl;
            return 0;
        }
    }

    return 0;
}

• Subtask 1: 11 / 11
• Subtask 2: 9 / 9
• Subtask 3: 14 / 14
• Subtask 4: 15 / 15
• Subtask 5: 9 / 9
• Subtask 6: 14 / 14
• Subtask 7: 15 / 15
• Subtask 8: 13 / 13