function heapIf(num_arr, size, n){

var largest = n;

var leftChild = 2 * n + 1;

var rightChild = 2 * n + 2;

if(leftChild < size && num_arr[leftChild] > num_arr[largest])

largest = leftChild;

if(rightChild < size && num_arr[rightChild] > num_arr[largest])

largest = rightChild;

if(largest != n){

num_arr[n] = [num_arr[largest], num_arr[largest] = num_arr[n]][0];

heapIf(num_arr, size, largest);

}

}

function heapSort(num_arr, s){

for(var c = s / 2 - 1; c >= 0; c--)

heapIf(num_arr, s, c);

for(var c = s - 1; c >= 0; c--){

num_arr[0] = [num_arr[c], num_arr[c] = num_arr[0]][0];

heapIf(num_arr, c, 0);

}

}

function mainFunc(){

var num_arr = [12, 33, 10, 45, 3, 15];

var size = num_arr.length;

heapSort(num_arr, size);

document.write("Sorting completed: ");

document.write(num_arr);

}

mainFunc();