Submission #1104681

#	Time	Username	Problem	Language	Result	Execution time	Memory
1104681		Champ_Naman	Group Photo (JOI21_ho_t3)	C++17	100 / 100	692 ms	392016 KiB

Main

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define nl '\n'

int pre1[5001][5001];
int pre2[5001][5001];

inline void solve(){
	int n;
	cin>>n;
	int a[n+1];
	for(int i=1; i<=n; i++) cin>>a[i];

	for(int i=1; i<=n; i++){
		for(int j=i+1; j<=n; j++){
			pre1[a[j]][a[i]]++;
			pre2[a[j]][a[i]]++;
		}
	}

	for(int i=1; i<=n; i++){
		for(int j=1; j<=n; j++){
			pre1[i][j] += pre1[i][j-1];
		}
	}

	for(int j=1; j<=n; j++){
		for(int i=1; i<=n; i++){
			pre2[i][j] += pre2[i-1][j];
		}
	}

	int dp[n+1];
	dp[0] = 0;
	for(int i=1; i<=n; i++){
		dp[i] = 1e18;
		int add = 0;

		for(int j=i; j>0; j--){
			add += pre1[j][n] - pre1[j][i];
			add += pre2[i][j] - pre2[j][j];

			dp[i] = min(dp[i], dp[j-1] + add);
		}
	}
	
	cout<<dp[n]<<nl;
}

signed main(){
	ios_base::sync_with_stdio(0);
	cin.tie(NULL);cout.tie(NULL);

	int t = 1;
	//cin>>t;
	while(t--) solve();

	return 0;
}

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