dunjo challenge game

#include<bits/stdc++.h>
using namespace std;

int main(){

    int n; cin>>n;
    int a[n];
    for(int i = 0; i<n; i++)cin>>a[i];
    int dp[100][100];
    memset(dp, 0, sizeof(dp));
    for(int i = 1; i<=n; i++)dp[i][i] = a[i-1];
    for(int i = 1; i<=n-1; i++){
        int k = i + 1;
        dp[i][k] = max(a[i-1],a[k-1]);
    }
    for(int len = 3; len<=n; len++){
        for(int left = 1; left<=n-len+1; left++){
            int right = left + len -1;
            int x = a[left-1] + max(dp[left+2][right],dp[left+1][right-1]);
            int y = a[right-1] + max(dp[left][right-2],dp[left+1][right-1]);
            dp[left][right] = max(x,y);

        }
    }
    cout<<dp[1][n]<<endl;
    return 0;
}