Submission #1102121

#	Time	Username	Problem	Language	Result	Execution time	Memory
1102121		MateiKing80	The short shank; Redemption (BOI21_prison)	C++14	100 / 100	1600 ms	90704 KiB

prison

#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using pll = pair<ll, ll>;
const ll INF = (ll)1e18 + 10;

int n, d, t;
vector<int> T;

struct ura
{
    int pos, inc;
    pll minn, seg;
};

pll faDP(ll lambda)
{

    stack<ura> U;
    pll seg;
    U.push({-1, 0, {INF, -1}, {INF, -1}});
    if (T[n - 1] > t)
    {
        U.push({n - 1, 0, {0, 0}, {0, 0}});
        seg = {INF, 0};
    }
    else
        seg = {1, 0};
    for (int i = n - 2; i >= 0; i --)
    {

        pll m = min(seg, U.top().minn);
        pll v = m;
        v.first += lambda;
        v.second ++;
        seg = min(seg, v);
        if (T[i] > t)
        {
            U.push({i, 0, m, seg});
            seg = {INF, 0};
        }
        else
        {
            int diff = t - T[i];
            seg.first ++;
            U.top().inc ++;
            U.top().minn.first ++;
            U.top().seg.first ++;
            while (U.size() > 1 && (U.top().pos - i) <= diff)
            {

                U.top().seg.first ++;
                seg = min(seg, U.top().seg);
                int inc = U.top().inc + 1;
                U.pop();
                U.top().inc += inc;
                U.top().minn.first += inc;
                U.top().seg.first += inc;
            }
        }
    }

    return min(seg, U.top().minn);
}

int main()
{

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

    cin >> n >> d >> t;
    T = vector<int>(n);
    for(int i = 0; i < n; i ++)
        cin >> T[i];
    ll l = 0;
    ll r = 4e6;
    ll c, x;
    while(l != r)
    {
        ll mid = (l + r) / 2;
        x = faDP(mid).second;
        if (x > d)
            l = mid + 1;
        else r = mid;
    }
    tie(c, x) = faDP(l);
    cout << c - d * l << endl;
    return 0;
}

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