Submission #1097188

#	Time	Username	Problem	Language	Result	Execution time	Memory
1097188		crafticat	Feast (NOI19_feast)	C++17	0 / 100	954 ms	26300 KiB

feast

#include "bits/stdc++.h"

using namespace std;

template<typename T>
using V = vector<T>;
using ll = long long;
using pi = pair<ll, ll>;

const ll INF = 1e18;

pi solve(const V<ll>& arr, ll k, ll p) {
    ll n = arr.size();
    V<V<pi>> dp(n + 1, V<pi>(2, {-INF, 0}));
    dp[0][0] = {0, 0};

    for (ll i = 1; i <= n; ++i) {
        dp[i][0] = {0, 0};
        pi prev0 = dp[i - 1][0];
        pi prev1 = dp[i - 1][1];

        // For l = 0
        dp[i][0] = max(dp[i][0], prev0);  // Carry forward dp[i-1][0]
        dp[i][0] = max(dp[i][0], {prev1.first - p, prev1.second + 1});  // Transfer from dp[i-1][1] with penalty

        // For l = 1
        dp[i][1] = max(dp[i][1], prev0);  // Transfer from dp[i-1][0]
        dp[i][1] = max(dp[i][1], {prev1.first + arr[i - 1], prev1.second});  // Keep dp[i-1][1] and add arr[i-1]
    }

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

int main() {
    ll n, k;
    cin >> n >> k;

    V<ll> arr(n);
    for (ll i = 0; i < n; ++i) {
        cin >> arr[i];
    }

    ll l = 0, r = 1e18;
    int iter = 0;
    while (r > l) {
        ll mid = l + (r - l + 1) / 2;
        if (solve(arr, k, mid).second >= k)
            l = mid;
        else
            r = mid - 1;

        if (++iter > 62) exit(5);  // Ensure no infinite loop
    }

    cout << solve(arr, k, l).first + l * k << "\n";
}

• Subtask 1: 0 / 4
• Subtask 2: 0 / 8
• Subtask 3: 0 / 18
• Subtask 4: 0 / 10
• Subtask 5: 0 / 11
• Subtask 6: 0 / 20
• Subtask 7: 0 / 29