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* Upgrade to Python 3.8 syntax
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136 lines
3.4 KiB
Python
136 lines
3.4 KiB
Python
#!/usr/bin/python3
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class Heap:
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"""
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>>> unsorted = [103, 9, 1, 7, 11, 15, 25, 201, 209, 107, 5]
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>>> h = Heap()
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>>> h.build_heap(unsorted)
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>>> h.display()
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[209, 201, 25, 103, 107, 15, 1, 9, 7, 11, 5]
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>>>
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>>> h.get_max()
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209
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>>> h.display()
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[201, 107, 25, 103, 11, 15, 1, 9, 7, 5]
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>>>
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>>> h.insert(100)
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>>> h.display()
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[201, 107, 25, 103, 100, 15, 1, 9, 7, 5, 11]
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>>>
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>>> h.heap_sort()
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>>> h.display()
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[1, 5, 7, 9, 11, 15, 25, 100, 103, 107, 201]
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>>>
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"""
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def __init__(self):
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self.h = []
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self.curr_size = 0
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def get_left_child_index(self, i):
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left_child_index = 2 * i + 1
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if left_child_index < self.curr_size:
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return left_child_index
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return None
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def get_right_child(self, i):
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right_child_index = 2 * i + 2
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if right_child_index < self.curr_size:
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return right_child_index
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return None
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def max_heapify(self, index):
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if index < self.curr_size:
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largest = index
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lc = self.get_left_child_index(index)
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rc = self.get_right_child(index)
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if lc is not None and self.h[lc] > self.h[largest]:
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largest = lc
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if rc is not None and self.h[rc] > self.h[largest]:
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largest = rc
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if largest != index:
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self.h[largest], self.h[index] = self.h[index], self.h[largest]
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self.max_heapify(largest)
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def build_heap(self, collection):
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self.curr_size = len(collection)
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self.h = list(collection)
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if self.curr_size <= 1:
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return
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for i in range(self.curr_size // 2 - 1, -1, -1):
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self.max_heapify(i)
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def get_max(self):
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if self.curr_size >= 2:
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me = self.h[0]
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self.h[0] = self.h.pop(-1)
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self.curr_size -= 1
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self.max_heapify(0)
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return me
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elif self.curr_size == 1:
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self.curr_size -= 1
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return self.h.pop(-1)
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return None
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def heap_sort(self):
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size = self.curr_size
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for j in range(size - 1, 0, -1):
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self.h[0], self.h[j] = self.h[j], self.h[0]
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self.curr_size -= 1
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self.max_heapify(0)
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self.curr_size = size
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def insert(self, data):
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self.h.append(data)
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curr = (self.curr_size - 1) // 2
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self.curr_size += 1
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while curr >= 0:
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self.max_heapify(curr)
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curr = (curr - 1) // 2
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def display(self):
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print(self.h)
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def main():
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for unsorted in [
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[],
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[0],
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[2],
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[3, 5],
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[5, 3],
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[5, 5],
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[0, 0, 0, 0],
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[1, 1, 1, 1],
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[2, 2, 3, 5],
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[0, 2, 2, 3, 5],
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[2, 5, 3, 0, 2, 3, 0, 3],
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[6, 1, 2, 7, 9, 3, 4, 5, 10, 8],
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[103, 9, 1, 7, 11, 15, 25, 201, 209, 107, 5],
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[-45, -2, -5],
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]:
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print("source unsorted list: %s" % unsorted)
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h = Heap()
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h.build_heap(unsorted)
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print("after build heap: ", end=" ")
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h.display()
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print("max value: %s" % h.get_max())
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print("delete max value: ", end=" ")
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h.display()
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h.insert(100)
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print("after insert new value 100: ", end=" ")
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h.display()
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h.heap_sort()
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print("heap sort: ", end=" ")
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h.display()
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print()
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if __name__ == "__main__":
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main()
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