Submission #412897

#	Time	Username	Problem	Language	Result	Execution time	Memory
412897		Tc14	The short shank; Redemption (BOI21_prison)	C++17	0 / 100	2086 ms	5216 KiB

prison

//#pragma GCC optimize("O3")
#include <bits/stdc++.h>
using namespace std;
#define ve vector
typedef long long ll;
typedef pair<int, int> pii;
const int INF = 1e9 + 10;

int main() {

    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    int n, d, t, m, ans;
    ve<int> T, P;
    ve<pii> A;
    ve<ve<int>> DP;

    cin >> n >> d >> t;

    T = ve<int>(n);
    for (int i = 0; i < n; i++) cin >> T[i];

    bool b = true;
    int e = INF;
    int l = -1;

    A.push_back({-1, -1});
    P.push_back(-1);

    for (int i = 0; i < n; i++) {
        if (T[i] > t) {
            if (!b) {
                int r = i - 1 + t - e;
                A.push_back({l, r});
                P.push_back(i - 1);
                e = INF;
                b = true;
                l = -1;
            }
        }
        else {
            if (b) {
                l = i;
                b = false;
            }
            e = min(e + 1, T[i]);
        }
    }
    if (!b) {
        A.push_back({l, n - 1}); 
        P.push_back(n - 1);
    }

    m = (int)A.size();
    DP = ve<ve<int>>(d + 1, ve<int>(m, INF));
    DP[0][0] = 0;

    for (int i = 1; i <= d; i++) {
        for (int j = 1; j < m; j++) {

            ve<pii> S;

            pii a = A[j];
            a.second = P[j];
            int s = a.second - a.first + 1;
            S.push_back(a);

            for (int k = j - 1; k >= 0; k--) {

                DP[i][j] = min(DP[i][j], DP[i - 1][k] + s);

                a = A[k];
                a.second = min(a.second, P[j]);

                while (S.size() > 0 && S.back().second <= a.second) {
                    s -= S.back().second - S.back().first + 1;
                    S.pop_back();
                }
                if (S.size() > 0) {
                    if (S.back().first <= a.second) {
                        a.second = S.back().second;
                        S.pop_back();
                    }
                }
                s += a.second - a.first + 1;
                S.push_back(a);

            }
        }
    }

    int s = 0;
    ve<pii> S;
    ans = INF;
    for (int j = m - 1; j >= 0; j--) {

        for (int i = 0; i <= d; i++) {
            ans = min(ans, DP[i][j] + s);
        }

        pii a = A[j];
        a.second = min(a.second, n - 1);

        while (S.size() > 0 && S.back().second <= a.second) {
            s -= S.back().second - S.back().first + 1;
            S.pop_back();
        }
        if (S.size() > 0) {
            if (S.back().first <= a.second) {
                a.second = S.back().second;
                S.pop_back();
            }
        }
        s += a.second - a.first + 1;
        S.push_back(a);

    }
    cout << ans << endl;

    return 0;
}

• Subtask 1: 0 / 15
• Subtask 2: 0 / 10
• Subtask 3: 0 / 20
• Subtask 4: 0 / 10
• Subtask 5: 0 / 25
• Subtask 6: 0 / 20