Example of a max heap implementation

max_heap.py

class MaxHeap(object):
    heap_values = None

    def __init__(self):
        self.heap_values = []

    def get_max(self):
        return self.heap_values[0]

    def insert(self, insert_me):
        self.heap_values.append(insert_me)  # Insert at end of array
        self._percolate_up(len(self.heap_values) - 1)  # Percolate up to root if needed

    def delete_max(self):
        if len(self.heap_values) == 0:
            return
        self._swap(0, len(self.heap_values) - 1)
        self.heap_values.pop(len(self.heap_values) - 1)  # Delete last element
        self._percolate_down(0)

    def _get_left(self, parent):
        index = (2 * parent) + 1
        if index >= len(self.heap_values):
            return -1
        return self.heap_values[index]

    def _get_right(self, parent):
        index = (2 * parent) + 2
        if index >= len(self.heap_values):
            return -1
        return self.heap_values[index]

    def _get_parent(self, index):
        parent = (index - 1) / 2
        return self.heap_values[parent]

    def _percolate_down(self, current_index):
        if len(self.heap_values) == 0:
            return
        node = self.heap_values[current_index]
        left = self._get_left(current_index)
        right = self._get_right(current_index)

        if left > right:
            if left > node:
                self._swap(current_index, (2 * current_index) + 1)
                self._percolate_down((2 * current_index) + 1)
        elif right > left:
            if right > node:
                self._swap(current_index, (2 * current_index) + 2)
                self._percolate_down((2 * current_index) + 2)

    def _percolate_up(self, current_index):
        if current_index == 0:
            return -1
        node = self.heap_values[current_index]
        parent = self._get_parent(current_index)
        if node > parent:
            self._swap(current_index, (current_index - 1) / 2)
            self._percolate_up((current_index - 1) / 2)

    def _swap(self, first, second):
        temp = self.heap_values[first]
        self.heap_values[first] = self.heap_values[second]
        self.heap_values[second] = temp


def main():
    x = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]
    y = MaxHeap()
    for val in x:
        y.insert(val)
        print y.heap_values

    for i in range(len(y.heap_values)):
        y.delete_max()
        print y.heap_values

if __name__ == "__main__":
    main()