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