Submission #1206645

#	Time	Username	Problem	Language	Result	Execution time	Memory
1206645		Trn115	Feast (NOI19_feast)	C++20	100 / 100	665 ms	23916 KiB

feast

#include <bits/stdc++.h>

#define int long long
#define fi first
#define se second
#define all(v) v.begin(), v.end()

using namespace std;
using pii = pair<int, int>;

constexpr int inf = 1e18;

int n, k;
vector<int> a;

pii f(int lambda) {
    vector<vector<pii>> dp(n + 1, vector<pii>(2, {-inf, -inf})); // sum, nos
    dp[0][0] = {0, 0};
    for (int i = 1; i <= n; ++i) {
        dp[i][0] = max(dp[i - 1][0], dp[i - 1][1]);
        dp[i][1] = max(
            make_pair(dp[i - 1][0].fi + a[i] - lambda, dp[i - 1][0].se + 1),
            make_pair(dp[i - 1][1].fi + a[i], dp[i - 1][1].se)
        );
    }
    return max(dp[n][0], dp[n][1]);
}

signed main() {
    cin.tie(0)->sync_with_stdio(0);

    cin >> n >> k;
    a.resize(n + 1);
    for (int i = 1; i <= n; ++i) cin >> a[i];

    int l = 0, r = 1e14;
    pair<int, int> ans;
    while (l <= r) {
        int mid = (l + r) / 2;
        ans = f(mid);
        if (ans.se == k) {
            l = mid;
            break;
        }
        if (ans.se > k) {
            l = mid + 1;
        } else {
            r = mid - 1;
        }
    }
    cout << ans.fi + l * k << '\n';
}

• 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