Ball Elimination

#include <bits/stdc++.h>
using namespace std;
#define ll long long int
 
ll ar[501],dp[501][501];
 
ll solve(ll i,ll j){
    if(i==j){
    	return 1;     
    }
    if(i>j){
    	return 0;     
    }
    if(dp[i][j]!=-1){
        return dp[i][j];  
    }
 	ll temp=ar[i],ans=100000001;     
  	for(ll k=i;k<=j;k++){
      	if(ar[k]==temp){
         	if(k==i){
          		ans=min(ans,1+solve(k+1,j));      
          	}
          	else{
             	if(k==j){
               		ans=min(ans,solve(i+1,k-1));      
              	}
              	else{
               		ans=min(ans,solve(i+1,k-1)+solve(k+1,j));
               	}
            }
        }
    }
   return dp[i][j]=ans;
}
 
int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);  
	ll n,i,j;
	cin>>n;
	for(i=0;i<n;i++){
		cin>>ar[i];     
	}
	for(i=0;i<501;i++){
		for(j=0;j<501;j++){
			dp[i][j]=-1;  
		}
	}
	cout<<solve(0,n-1);
	return 0;
}