9.求一个数组最大值(递归)

int GetMax(int arr[], int left, int right)
{
  if (left == right) return arr[right];
    
  int mid = left + ((left-right)>>1);
    
  int leftMax = GetMax(arr, left, mid);
  int rightMax = GetMax(arr, mid+1, right);
    
  return leftMax > rightMax ? leftMax : rightMax;

}