Submission #1211282

#	Time	Username	Problem	Language	Result	Execution time	Memory
1211282		malta	Feast (NOI19_feast)	C++20	18 / 100	52 ms	2632 KiB

feast

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll INF = 4e18;

int N, K;
vector<ll> A;

pair<ll,int> solve(ll m) {
    ll dp0 = 0, dp1 = -INF;
    int c0 = 0, c1 = 0;
    for (int i = 0; i < N; i++) {
        ll x = A[i];
        ll ndp1;
        int nc1;
        if (dp1 + x >= dp0 + x - m) {
            ndp1 = dp1 + x;
            nc1 = c1;
        } else {
            ndp1 = dp0 + x - m;
            nc1 = c0 + 1;
        }
        ll ndp0;
        int nc0;
        if (dp0 >= dp1) {
            ndp0 = dp0;
            nc0 = c0;
        } else {
            ndp0 = dp1;
            nc0 = c1;
        }
        dp0 = ndp0; c0 = nc0;
        dp1 = ndp1; c1 = nc1;
    }
    if (dp0 >= dp1) return {dp0, c0};
    return {dp1, c1};
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> N >> K;
    A.resize(N);
    for (int i = 0; i < N; i++) {
        cin >> A[i];
    }

    ll lo = -1e12, hi = 1e12, bestm = 0;
    while (lo <= hi) {
        ll mid = (lo + hi) >> 1;
        auto res = solve(mid);
        if (res.second <= K) {
            bestm = mid;
            hi = mid - 1;
        } else {
            lo = mid + 1;
        }
    }

    auto res = solve(bestm);
    ll answer = res.first + bestm * K;
    cout << answer << "\n";
    return 0;
}

• Subtask 1: 0 / 4
• Subtask 2: 0 / 8
• Subtask 3: 18 / 18
• Subtask 4: 0 / 10
• Subtask 5: 0 / 11
• Subtask 6: 0 / 20
• Subtask 7: 0 / 29