Submission #692761

#	Time	Username	Problem	Language	Result	Execution time	Memory
692761		owoovo	Group Photo (JOI21_ho_t3)	C++14	100 / 100	409 ms	165228 KiB

Main

#include<bits/stdc++.h>
using namespace std;
int dp[5010],a[5010][5010]={},ori[5010],pre[5010][5010]={};
int q(int li,int ri,int dj,int uj){
    return pre[ri][uj]-pre[li-1][uj]-pre[ri][dj-1]+pre[dj-1][li-1];
}
int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    int n;
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>ori[i];
        dp[i]=1000000000;
    }
    for(int i=1;i<=n;i++){
        for(int j=i+1;j<=n;j++){
            if(ori[i]<ori[j]){
                a[ori[i]][ori[j]]=1;
            }
        }
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            pre[i][j]=pre[i-1][j]+pre[i][j-1]-pre[i-1][j-1]+a[i][j];
        }
    }
    for(int i=1;i<=n;i++){
        dp[i]=dp[i-1]+i-1-q(1,i,i,i);
        for(int j=0;j<i;j++){
            dp[i]=min(dp[i],q(j+1,i,j+1,i)+(i-j)*j-q(1,j,j+1,i)+dp[j]);
        }
    }
    cout<<dp[n]<<"\n";
    return 0;
}

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