Submission #1078191

#	Time	Username	Problem	Language	Result	Execution time	Memory
1078191		South_Cloud	Feast (NOI19_feast)	C++17	100 / 100	121 ms	14060 KiB

feast

	#include <bits/stdc++.h>

#define fi first
#define se second

using namespace std;

const int N = 3e5 + 7;

int n, k, a[N];

void input() {
    cin >> n >> k;
    for(int i = 1; i <= n; i++) {
        cin >> a[i];
    }
}

pair<long long, int> dp[N][2];

pair<long long, long long> solveLambda(long long x) {
    dp[1][0] = make_pair(0, 0);
    dp[1][1] = make_pair(a[1] - x, 1);
    for(int i = 2; 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] - x, 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]);
}

void solve() {
    long long l = 0, r = 1e18;
    while(r - l > 1) {
        long long mid = (l + r) >> 1;
        pair<long long, long long> cur = solveLambda(mid);
        if(cur.se >= k) l = mid;
            else r = mid;
    }
    cout << solveLambda(l).fi + l * k;
}

int main() {
    cin.tie(NULL)->ios_base::sync_with_stdio(NULL);
    //freopen(" .inp", "r", stdin);
    //freopen(" .out", "w", stdout);
    input();
    solve();
    return 0;
}

• 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