optimal strategy for a game by DP

#include<iostream>
#include<math.h>
using namespace std;

  int OptimalStrategyOfGame(int arr[],int n){
    int op_val[n][n];
    for(int gap=0;gap<n;gap++){
      for(int i=0,j=gap;j<n;i++,j++){
        int x=(i+2<=j)?op_val[i+2][j]:0;
        int y=(i+1<=j-1)?op_val[i+1][j-1]:0;
        int z=(i<=j-2)?op_val[i][j-2]:0;
        op_val[i][j]=max((arr[i]+min(x,y)),(arr[j]+min(y,z)));
        }
      }
      return op_val[0][n-1];
    }

int main(){
  int arr1[] = { 8, 15, 3, 7 };
    int n = 4;
   cout<<OptimalStrategyOfGame(arr1, n)<<endl;

    int arr2[] = { 2, 2, 2, 2 };
    n = 4;
   cout<<OptimalStrategyOfGame(arr2, n)<<endl;

    int arr3[] = { 20, 30, 2, 2, 2, 10 };
    n = 6;
    cout<<OptimalStrategyOfGame(arr3, n)<<endl;
    return 0;
  }