Submission #1246417

#	Time	Username	Problem	Language	Result	Execution time	Memory
1246417		rhombus	Feast (NOI19_feast)	C++20	18 / 100	896 ms	34420 KiB

feast

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const ll inf = 1e18;

pair <ll, int> calc(vector <int> &a, ll lambda) {
    int n = (int) a.size();
    vector dp(n + 1, vector (2, 0ll));
    vector mn(n + 1, vector (2, 0ll));
    dp[0][0] = 0;
    dp[0][1] = -inf; 
    mn[0][0] = 0;
    mn[0][1] = inf;
    for (int i = 1; i <= n; i++) {
        int x = a[i - 1];
        dp[i][0] = dp[i - 1][0];
        mn[i][0] = mn[i - 1][0];
        if (dp[i - 1][1] > dp[i][0]) {
            dp[i][0] = dp[i - 1][1];
            mn[i][0] = mn[i - 1][1];
        } else if (dp[i - 1][1] == dp[i][0]) {
            mn[i][0] = min(mn[i - 1][1], mn[i][0]);
        }
        dp[i][1] = x + dp[i - 1][1];
        mn[i][1] = mn[i - 1][1];
        if (lambda + x + dp[i - 1][0] > dp[i][1]) {
            dp[i][1] = lambda + x + dp[i - 1][0];
            mn[i][1] = mn[i - 1][0] + 1;
        } else if (lambda + x + dp[i - 1][0] == dp[i][1]) {
            mn[i][1] = min(mn[i][1], 1 + mn[i - 1][0]);
        }
    }
    pair <ll, ll> ans;
    ans.first = max(dp[n][0], dp[n][1]);
    if (dp[n][0] == dp[n][1]) {
        ans.second = min(mn[n][0], mn[n][1]); 
    } else if (dp[n][0] > dp[n][1]) {
        ans.second = mn[n][0];
    } else {
        ans.second = mn[n][1];
    }
    return ans;
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    int n, k;
    cin >> n >> k;
    vector <int> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    ll l = -1e12 - 7, r = 1e12 + 7;
    while (l <= r) {
        ll mid = (l + r) / 2;
        if (calc(a, mid).second <= k) {
            l = mid + 1;
        } else {
            r = mid - 1;
        }
    }
    ll score = calc(a, r).first - calc(a, r).second * (ll) r;
    cout << max(0ll, score) << '\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