제출 #1301674

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1301674		red_souls	Feast (NOI19_feast)	C++20	100 / 100	134 ms	12172 KiB

feast

#include <bits/stdc++.h>
#define ll long long
#define task "FEAST"
using namespace std;

const int N = 3e5 + 16;
const ll INF = 1e18;
int n, K;
ll a[N];

namespace sub7 {

    pair <ll, ll> dp[N][2];

    pair <ll, ll> dpCalc(ll k) {
        for (int i = 0; i <= n; i++) {
            dp[i][0] = dp[i][1] = {-INF, 0};
        }

        dp[0][0] = {0, 0};
        for (int i = 1; i <= n; i++) {
            dp[i][0] = max(dp[i][0], dp[i - 1][0]);
            dp[i][0] = max(dp[i][0], dp[i - 1][1]);

            dp[i][1] = max(dp[i][1], make_pair(dp[i - 1][0].first + a[i] - k, dp[i - 1][0].second + 1));
            dp[i][1] = max(dp[i][1], make_pair(dp[i - 1][1].first + a[i], dp[i - 1][1].second));
        }

        return max(dp[n][0], dp[n][1]);
    }

    void solve() {
        /*
        ll l = 0, r = INF, mid, result;
        while (l <= r) {
            mid = l + r >> 1;
            if (dpCalc(mid).second >= K) {
                l = mid + 1;
                result = mid;
            }
            else {
                r = mid - 1;
            }
        }
        cout << dpCalc(result).first + result * K;
        */
        ll lo = 0;
        ll hi = 1e18;
        while (lo < hi) {
            ll mid = (lo + hi + 1) / 2;
            dpCalc(mid).second >= K ? lo = mid : hi = mid - 1;
        }

        cout << dpCalc(lo).first + lo * K << endl;
    }
}

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

    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }

    cin >> n >> K;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    sub7 :: solve();

    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

feast.cpp: In function 'int main()':
feast.cpp:64:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
feast.cpp:65:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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