//--------------------------------------------------------------------------------------------------
// Returns true if arr[i..n-1] represents a
// max-heap
bool isHeap(int arr[], int index, int size)
{
if (index > (size - 2)/2) // If a leaf node
return true;
// If an internal node and is greater than its children, and same is recursively true for the
// children
if ( arr[index] >= arr[2 * index + 1] &&
arr[index] >= arr[2 * index + 2] &&
isHeap(arr, 2 * index + 1, size) &&
isHeap(arr, 2*index + 2, size) )
return true;
return false;
}
// Returns true if arr[i..n-1] represents a
// max-heap
bool isHeap(int arr[], int i, int n)
{
// If a leaf node
if (i > (n - 2)/2)
return true;
// If an internal node and is greater than its children, and
// same is recursively true for the children
if (arr[i] >= arr[2*i + 1] && arr[i] >= arr[2*i + 2] &&
isHeap(arr, 2*i + 1, n) && isHeap(arr, 2*i + 2, n))
return true;
return false;
}
// Driver program
int main()
{
int arr[] = {90, 15, 10, 7, 12, 2, 7, 3};
int size = sizeof(arr) / sizeof(int);
isHeap(arr, 0, size)? printf("Yes"): printf("No");
return 0;
}