Submission #624270

#	Time	Username	Problem	Language	Result	Execution time	Memory
624270		Ronin13	Group Photo (JOI21_ho_t3)	C++14	100 / 100	413 ms	165456 KiB

Main

#include<bits/stdc++.h>
#define ll long long
#define ull unsigned ll
#define f first
#define s second
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pb push_back
#define epb emplace_back
using namespace std;

const int NMAX = 5005;
int pre[NMAX][NMAX];
int dp[NMAX][NMAX];
int DP[NMAX];
int dpb[NMAX];
int main(){
    int n; cin >> n;
    int a[n + 1];
    for(int i = 1; i <= n; i++) cin >> a[i];
    int pos[n + 1];
    for(int i = 1; i <= n; i++) pos[a[i]] = i;
    for(int i = 1; i <= n; i++){
        dp[i][0] = 0;
        for(int j = 1; j <= n; j++){
            dp[i][j] = dp[i][j - 1];
            if(pos[i] > pos[j]) dp[i][j]++;
        }
    }
    for(int i = n; i >= 1; i--){
        pre[i][i] = i - 1 - dp[i][i];
        for(int j = i + 1; j <= n; j++){
            pre[i][j] = pre[i][j - 1] + dp[j][j] - dp[j][i - 1] + i - 1 -  dp[j][i - 1] ;
        }
    }
    DP[0] = 0;
    for(int i= 1; i <= n; i++){
        DP[i] = 1e9;
        int mni;
        for(int j = 0; j < i; j++){
            DP[i] = min(DP[i], pre[j + 1][i] + DP[j]);
        }

    }
    cout << DP[n];
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:39:13: warning: unused variable 'mni' [-Wunused-variable]
   39 |         int mni;
      |             ^~~

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