#include <stdio.h>
#include <stdlib.h>

int *arr;
size_t len = 0;

int
get_parent(int i)
{
	return (i - 1) / 2;
}

int
get_left_child(int i)
{
	return i * 2 + 1;
}

int
get_right_child(int i)
{
	return i * 2 + 2;
}

void
heapify_down(int i)
{
	int l = get_left_child(i);
	int r = get_right_child(i);

	if (i >= len || l >= len) {
		return;
	}

	int left_val = arr[l];
	int right_val = arr[r];
	int val = arr[i];

	if (right_val > left_val && val > left_val) {
		arr[i] = left_val;
		arr[l] = val;
		heapify_down(l);
	} else if (left_val > right_val && val > right_val) {
		arr[i] = right_val;
		arr[r] = val;
		heapify_down(r);
	}
}

void
heapify_up(int i)
{
	if (i == 0) {
		return;
	}

	int p = get_parent(i);
	int parent_val = arr[p];
	int child_val = arr[i];

	if (parent_val > child_val) {
		arr[i] = parent_val;
		arr[p] = child_val;
		heapify_up(p);
	}
}

void
insert(int val)
{
	arr = realloc(arr, ++len * sizeof(int));
	arr[len - 1] = val;
	heapify_up(len - 1);
}

int
delete()
{
	if (len == 0) {
		return -1;
	}
	int val = arr[0];
	if (len == 1) {
		free(arr);
		return val;
	}

	arr[0] = arr[--len];
	heapify_down(0);
	arr = realloc(arr, len * sizeof(int));
	return val;

}

int
main()
{
	arr = calloc(len, sizeof(int));
	insert(5);
	insert(3);
	insert(9);
	insert(7);
	for (int i = 0; i < len; ++i) {
		printf("%d ", arr[i]);
	}
	printf("\n");
	delete();
	for (int i = 0; i < len; ++i) {
		printf("%d ", arr[i]);
	}
	printf("\n");
	return 0;
}