Submission #1151431

#	Time	Username	Problem	Language	Result	Execution time	Memory
1151431		irmuun	Group Photo (JOI21_ho_t3)	C++20	64 / 100	5096 ms	98268 KiB

Main

#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define pb push_back
#define ff first
#define ss second
#define all(s) s.begin(),s.end()
#define rall(s) s.rbegin(),s.rend()

int main(){
    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
    int n;
    cin>>n;
    int p[n+5],f[n+5];
    for(int i=1;i<=n;i++){
        cin>>p[i];
        f[p[i]]=i;
    }
    int need[n+5][n+5];
    memset(need,0,sizeof need);
    for(int r=1;r<=n;r++){
        int cur=0;
        need[r][r]=0;
        for(int l=r-1;l>=1;l--){
            for(int i=l+1;i<=r;i++){
                if(f[i]>f[l]){
                    cur++;
                }
            }
            need[l][r]=cur;
        }
    }
    int cnt[n+5][n+5];
    memset(cnt,0,sizeof cnt);
    for(int l=1;l<=n;l++){
        int left[n+5],len=0;
        int pre[n+5],pos[n+5];
        for(int i=1;i<=n;i++){
            if(p[i]>=l){
                len++;
                pos[p[i]]=len;
            }
        }
        pre[0]=0;
        for(int i=l;i<=n;i++){
            pre[i-l+1]=pre[i-l]+pos[i];
        }
        int cur=0;
        for(int r=l;r<=n;r++){
            int x=r-l+1;
            cnt[l][r]=need[l][r]+pre[x]-(x*(x+1)/2);
        }
    }
    int dp[n+5];
    fill(dp,dp+n+1,1e9);
    dp[0]=0;
    for(int l=1;l<=n;l++){
        for(int r=l;r<=n;r++){
            dp[r]=min(dp[r],dp[l-1]+cnt[l][r]);
        }
    }
    cout<<dp[n];
}

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 32 / 32
• Subtask 4: 20 / 20
• Subtask 5: 0 / 36