Submission #1122212

#	Time	Username	Problem	Language	Result	Execution time	Memory
1122212		mingga	Feast (NOI19_feast)	C++17	100 / 100	157 ms	16204 KiB

feast

#include "bits/stdc++.h"

using namespace std;

#define ln "\n"
#define pb push_back
#define fi first
#define se second
#define all(x) (x).begin(), (x).end()
#define sz(x) ((int)(x).size())
#define int long long
const int mod = 1e9 + 7;
const int inf = 2e18;
const int N = 3e5 + 7;
int n, k, a[N];
pair<int, int> dp[N][2];     

pair<int, int> calc(int pen) {
    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][1].fi + a[i], dp[i - 1][1].se),
                        make_pair(dp[i - 1][0].fi + a[i] - pen, dp[i - 1][0].se + 1));
    }
    return max(dp[n][0], dp[n][1]);
}

signed main() {
    cin.tie(0) -> sync_with_stdio(0);
    cin >> n >> k;
    for(int i = 0; i < n; i++) cin >> a[i];
    dp[0][0] = dp[0][1] = {0, 0};
    auto solve_lambda = [&](int lmb) {
        pair<int, int> dp[n][2];

        dp[0][0] = {0, 0};
        dp[0][1] = {a[0] - lmb, 1};

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

        return max(dp[n - 1][0], dp[n - 1][1]);
    };
    int l = 0, r = 1e18; 
    int ans = 0;
    while(l <= r) {
        int m = (l + r) >> 1;
        if(solve_lambda(m).se >= k) {
            ans = m;
            l = m + 1;
        } else r = m - 1;
    }
    cout << solve_lambda(ans).fi + k *ans;
    cerr << "\nTime: " << clock() * 1000 / CLOCKS_PER_SEC;
}

• 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