Submission #1211262

#	Time	Username	Problem	Language	Result	Execution time	Memory
1211262		malta	Feast (NOI19_feast)	C++20	18 / 100	82 ms	10888 KiB

feast

#include <bits/stdc++.h>
using namespace std;
using ll  = long long;
using i128 = __int128_t;

pair<i128,int> dpc(const vector<ll>& pfs, i128 C) {
    int n = pfs.size() - 1;
    vector<i128> dp(n+1, (i128)LLONG_MIN * 2);
    vector<int> cnt(n+1, 0);
    dp[0] = 0;
    cnt[0] = 0;
    i128 val = 0;
    int cnt0 = 0;
    for (int i = 1; i <= n; i++) {
        dp[i]  = dp[i-1];
        cnt[i] = cnt[i-1];
        i128 dpi = val + (i128)pfs[i] + C;
        int ci   = cnt0 + 1;
        if (dpi > dp[i]) {
            dp[i]  = dpi;
            cnt[i] = ci;
        }
        i128 cur = dp[i] - (i128)pfs[i];
        if (cur > val) {
            val  = cur;
            cnt0 = cnt[i];
        }
    }
    return { dp[n], cnt[n] };
}

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

    int n, k;
    cin >> n >> k;
    vector<ll> a(n+1), pfs(n+1, 0);
    for (int i = 1; i <= n; i++){
        cin >> a[i];
        pfs[i] = pfs[i-1] + a[i];
    }

    if (*max_element(a.begin()+1, a.end()) <= 0) {
        cout << 0 << "\n";
        return 0;
    }

    i128 lo = -(i128)1e14, hi = (i128)1e14;
    i128 c0 = hi, dp0 = 0;
    while (lo <= hi) {
        i128 mid = lo + ((hi - lo) >> 1);
        auto [dpC, kC] = dpc(pfs, mid);
        if (kC >= k) {
            c0  = mid;
            dp0 = dpC;
            hi  = mid - 1;
        } else {
            lo = mid + 1;
        }
    }

    i128 ans128 = dp0 - c0 * k;
    ll answer = (ll)ans128;
    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