Submission #1156394

#	Time	Username	Problem	Language	Result	Execution time	Memory
1156394		dnnnda	Group Photo (JOI21_ho_t3)	C++20	100 / 100	562 ms	196564 KiB

Main

#include<bits/stdc++.h>
using namespace std;
#define S second
#define F first
#define ll long long
//#define int long long
//#pragma GCC optimize("Ofast, unroll-loop")
//#pragma GCC target("avx,avx2")
#pragma GCC optimize("O3")
const int inf=0x3f3f3f3f;
const ll inff=0x3f3f3f3f3f3f3f3f;
//const int X=1000000007;
const int X=998244353;

int h[5005], cost1[5005][5005], cost2[5005][5005], dp[5005];

signed main(){
    ios::sync_with_stdio(0), cin.tie(0);
    memset(cost1,0,sizeof cost1);
    memset(cost2,0,sizeof cost2);
    int n; cin >> n;
    for(int i=1 ; i<=n ; i++) cin >> h[i];

    for(int i=1 ; i<n ; i++) for(int j=i+1 ; j<=n ; j++){
        if(h[i]<h[j]){
            cost2[1][h[j]]++;
            cost2[h[i]+1][h[j]]--;
        }
        else{
            cost1[1][h[i]]++;
            cost1[h[j]+1][h[i]]--;

            cost1[1][h[j]]++;
            cost1[1][h[i]]--;
            cost1[h[j]+1][h[j]]--;
            cost1[h[j]+1][h[i]]++;
            cost2[1][h[j]]++;
            cost2[1][h[i]]--;
            cost2[h[j]+1][h[j]]--;
            cost2[h[j]+1][h[i]]++;
        }
    }
    for(int i=1 ; i<=n ; i++) for(int j=1 ; j<=n ; j++)
        cost1[i][j]+=cost1[i][j-1], cost2[i][j]+=cost2[i][j-1];
    for(int i=1 ; i<=n ; i++) for(int j=1 ; j<=n ; j++)
        cost1[i][j]+=cost1[i-1][j], cost2[i][j]+=cost2[i-1][j];
    for(int i=1 ; i<=n ; i++) for(int j=i ; j<=n ; j++){
        //cout << "cost1[" << i << "][" << j << "]=" << cost1[i][j] << '\n';
        //cout << "cost2[" << i << "][" << j << "]=" << cost2[i][j] << '\n';
    }
    dp[1]=min(cost1[1][1],cost2[1][1]);
    for(int i=2 ; i<=n ; i++){
        dp[i]=inf;
        for(int j=0 ; j<i ; j++) dp[i]=min(dp[i],dp[j]+min(cost1[j+1][i],cost2[j+1][i]));
        //cout << "dp[" << i << "]=" << dp[i] << '\n';
    }
    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