Submission #1021724

#	Time	Username	Problem	Language	Result	Execution time	Memory
1021724		12345678	The short shank; Redemption (BOI21_prison)	C++17	35 / 100	778 ms	136600 KiB

prison

#include <bits/stdc++.h>

using namespace std;

const int nx=4e3+5;

int n, d, T, dp[nx][nx], c[nx][nx], t[nx], lst;

void solve(int l, int r, int layer, int optl, int optr)
{
    if (r<l) return;
    int md=(l+r)/2;
    //cout<<"debug "<<md<<' '<<optl<<' '<<optr<<'\n';
    pair<int, int> mn={INT_MAX, 0};
    for (int i=optl; i<=min(optr, md); i++) mn=min(mn, {dp[layer-1][i-1]+c[i][md], i});
    //cout<<"md "<<md<<' '<<mn.first<<' '<<mn.second<<'\n';
    dp[layer][md]=mn.first;
    solve(l, md-1, layer, optl, mn.second);
    solve(md+1, r, layer, mn.second, optr); 
}

int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    cin>>n>>d>>T;
    for (int i=1; i<=n; i++) cin>>t[i];
    for (int i=0; i<=n; i++) for (int j=0; j<=n; j++) dp[i][j]=1e9;
    dp[0][0]=0;
    for (int i=1; i<=n; i++)
    {
        int cnt=0, lst=1e9;
        for (int j=i; j<=n; j++) lst=min(lst+1, t[j]), cnt+=(lst<=T), c[i][j]=cnt;
    }
    for (int i=1; i<=d+1; i++) solve(i, n, i, i, n);
    //for (int i=1; i<=d+1; i++) for (int j=1; j<=n; j++) cout<<i<<' '<<j<<' '<<dp[i][j]<<'\n';
    cout<<dp[d+1][n];
}

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