public class ArrayHeapChecker {
	//Check if the given array is a representation of a binary tree
		public static boolean isBinaryTree(Integer[] array) {
			if (array == null) {
				return false;
			}

			else if (array.length == 1 || array.length == 0) {
				return true;
			}

			for (int i=1; i<array.length; i++) {
				if (array[i]!=null && array[(int)((i-1)/2)]== null) {
					return false;
				}
			}

			return true;
		}

		//Check if the given array is a complete binary tree
		public static boolean isCompleteBinaryTree(Integer[] array) {
			if(!isBinaryTree(array)) {
				return false;
			}
			// If index assigned to current node is more than number of nodes in tree, then tree is not complete
	        int numberOfNodes = 0;
	        for (int i=0; i<array.length; i++) {
	        	if (array[i]!=null) {
	        		numberOfNodes++;
	        	}
	        }

	        for (int j=0; j<array.length; j++) {
	        	if (array[j]!=null && j >= numberOfNodes) {
	        		return false;
	        	}
	        }
			return true;
		}

		//Check if the given array is a min-heap
		public static boolean isMinHeap(Integer[] array) {
			if(!isCompleteBinaryTree(array)) {
				return false;
			}

			for (int i=1; i<array.length; i++) {
				if (array[i]!=null && (array[(int)((i-1)/2)] > array[i])) {
					return false;
				}
			}
			return true;
		}
}