mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-30 16:31:08 +00:00
88 lines
2.4 KiB
Python
88 lines
2.4 KiB
Python
class BinaryHeap:
|
|
"""
|
|
A max-heap implementation in Python
|
|
>>> binary_heap = BinaryHeap()
|
|
>>> binary_heap.insert(6)
|
|
>>> binary_heap.insert(10)
|
|
>>> binary_heap.insert(15)
|
|
>>> binary_heap.insert(12)
|
|
>>> binary_heap.pop()
|
|
15
|
|
>>> binary_heap.pop()
|
|
12
|
|
>>> binary_heap.get_list
|
|
[10, 6]
|
|
>>> len(binary_heap)
|
|
2
|
|
"""
|
|
|
|
def __init__(self):
|
|
self.__heap = [0]
|
|
self.__size = 0
|
|
|
|
def __swap_up(self, i: int) -> None:
|
|
"""Swap the element up"""
|
|
temporary = self.__heap[i]
|
|
while i // 2 > 0:
|
|
if self.__heap[i] > self.__heap[i // 2]:
|
|
self.__heap[i] = self.__heap[i // 2]
|
|
self.__heap[i // 2] = temporary
|
|
i //= 2
|
|
|
|
def insert(self, value: int) -> None:
|
|
"""Insert new element"""
|
|
self.__heap.append(value)
|
|
self.__size += 1
|
|
self.__swap_up(self.__size)
|
|
|
|
def __swap_down(self, i: int) -> None:
|
|
"""Swap the element down"""
|
|
while self.__size >= 2 * i:
|
|
if 2 * i + 1 > self.__size:
|
|
bigger_child = 2 * i
|
|
else:
|
|
if self.__heap[2 * i] > self.__heap[2 * i + 1]:
|
|
bigger_child = 2 * i
|
|
else:
|
|
bigger_child = 2 * i + 1
|
|
temporary = self.__heap[i]
|
|
if self.__heap[i] < self.__heap[bigger_child]:
|
|
self.__heap[i] = self.__heap[bigger_child]
|
|
self.__heap[bigger_child] = temporary
|
|
i = bigger_child
|
|
|
|
def pop(self) -> int:
|
|
"""Pop the root element"""
|
|
max_value = self.__heap[1]
|
|
self.__heap[1] = self.__heap[self.__size]
|
|
self.__size -= 1
|
|
self.__heap.pop()
|
|
self.__swap_down(1)
|
|
return max_value
|
|
|
|
@property
|
|
def get_list(self):
|
|
return self.__heap[1:]
|
|
|
|
def __len__(self):
|
|
"""Length of the array"""
|
|
return self.__size
|
|
|
|
|
|
if __name__ == "__main__":
|
|
import doctest
|
|
|
|
doctest.testmod()
|
|
# create an instance of BinaryHeap
|
|
binary_heap = BinaryHeap()
|
|
binary_heap.insert(6)
|
|
binary_heap.insert(10)
|
|
binary_heap.insert(15)
|
|
binary_heap.insert(12)
|
|
# pop root(max-values because it is max heap)
|
|
print(binary_heap.pop()) # 15
|
|
print(binary_heap.pop()) # 12
|
|
# get the list and size after operations
|
|
print(binary_heap.get_list)
|
|
print(len(binary_heap))
|