Submission #1273558

#	Time	Username	Problem	Language	Result	Execution time	Memory
1273558		KindaGoodGames	The short shank; Redemption (BOI21_prison)	C++20	0 / 100	34 ms	2648 KiB

prison

// #pragma GCC optimize("O3, unroll-loops, Ofast")
#include<bits/stdc++.h>

using namespace std;

vector<int> arr;

const int MAXN = 4000; 
const int MAXD = 4; 
int C[2][MAXN]; 
int dp[MAXD][MAXN];
int n,d,t;
int INF = numeric_limits<int>::max()/2;
int cost(int l, int r){
    int time = INF;
    int cnt = 0;
    for(int i = l; i <= r; i++){
        time = min(time+1, arr[i]);
        if(time <= t){
            cnt++;
        }
    }

    return cnt;
}   

void calc(int k, int l, int r, int optl, int optr){
    if(l >= r) return;
    int mid = (l+r)/2;  
    int opt = -1; 
    for(int j = optl; j <= min(optr,mid); j++){
        int c = cost(j,mid);
        // int c = C[j][mid];
        if(dp[k][mid] > dp[k-1][j-1] + c){  
            opt = j;
            dp[k][mid] = dp[k-1][j-1] + c;
        } 
    } 
    calc(k,l,mid,optl,opt);
    calc(k,mid+1,r,opt,optr);
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> d >> t;
 
    arr.resize(n);
    for(int i = 0; i < n; i++){
        cin >> arr[i];
    }
    // C.resize(n, vector<int>(n));
    for(int i = 0; i < 1; i++){
        int time = INF;
        int cnt = 0;
        for(int j = i; j < n; j++){
            time = min(time+1, arr[j]);
            if(time <= t){
                cnt++;
            }
            C[i][j] = cnt;
        }
    } 

    // d pillows, [0;i]
    // dp.resize(d+1, vector<int>(n, INF)); 
    for(int i = 0; i < MAXD; i++){
        for(int j = 0; j < MAXN; j++){
            dp[i][j] = INF;
        }
    }

    for(int i = 0; i < n; i++){
        dp[0][i] = C[0][i];
    }
    for(int i = 1; i <= d; i++){
        calc(i,0,n,0,n);
    }
    cout << dp[d][n-1] << endl;
}

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