114 lines
3.4 KiB
Python
114 lines
3.4 KiB
Python
"""
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排序 - 冒泡排序(简单O(N**2)) / 归并排序(高级O(N*log2N))
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冒泡排序
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34, 99, 52, 11, 47, 68, 50, 84
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34, 52, 11, 47, 68, 50, 84, 99
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34, 11, 47, 52, 50, 68, 84
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11, 34, 47, 50, 52, 68
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快速排序
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34, 99, 52, 11, 47, 68, 50, 84
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{34, 11, 47}, {50}, {99, 52, 68, 84}
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{11}, {34}, {47}, {50}, {52, 68, 84}, {99}
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{11}, {34}, {47}, {50}, {52}, {68, 84}, {99}
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{11}, {34}, {47}, {50}, {52}, {68}, {84}, {99}
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归并排序 - 分治法(divide-and-conquer)
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34, 99, 52, 11, 47, 68, 50, 84
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{34, 99, 52, 11}, {47, 68, 50, 84}
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{34, 99}, {52, 11}, {47, 68}, {50, 84}
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{34}, {99}, {52}, {11}, {47}, {68}, {50}, {84}
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{34, 99}, {11, 52}, {47, 68}, {50, 84}
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{11, 34, 52, 99}, {47, 50, 68, 84}
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{11, 34, 47, 50, 52, 68, 84, 99}
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在使用分治法的时候通常都会使用到递归调用这种编程手段
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一个函数直接或间接的调用了自身就称之为递归调用
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"""
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# 9 1 2 3 4 5 6 7 8
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# 2 3 4 5 6 7 8 9 1
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# *前面的参数称为位置参数, *后面的参数称为命名关键字参数
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# 所谓命名关键字参数就是调用函数时必须以"参数名=参数值"的形式传入参数
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def bubble_sort(origin_items, *, comp=lambda x, y: x > y):
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"""冒泡排序"""
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items = origin_items[:]
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length = len(items)
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for i in range(1, length):
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swapped = False
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for j in range(0, length - i):
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if comp(items[j], items[j + 1]):
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items[j], items[j + 1] = items[j + 1], items[j]
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swapped = True
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if swapped:
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swapped = False
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for j in range(length - i - 1, i - 1, -1):
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if comp(items[j - 1], items[j]):
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items[j - 1], items[j] = items[j], items[j - 1]
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swapped = True
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if not swapped:
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break
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return items
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def merge(list1, list2, comp=lambda x, y: x <= y):
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""""有序合并(将两个有序的列表合并成一个新的有序的列表)"""
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list3 = []
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index1, index2 = 0, 0
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while index1 < len(list1) and index2 < len(list2):
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if comp(list1[index1], list2[index2]):
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list3.append(list1[index1])
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index1 += 1
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else:
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list3.append(list2[index2])
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index2 += 1
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list3 += list1[index1:]
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list3 += list2[index2:]
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return list3
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def merge_sort(origin_items, comp=lambda x, y: x <= y):
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"""归并排序"""
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if len(origin_items) <= 1:
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return origin_items[:]
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mid = len(origin_items) // 2
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left = merge_sort(origin_items[:mid], comp)
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right = merge_sort(origin_items[mid:], comp)
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return merge(left, right, comp)
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class Person:
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"""人"""
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def __init__(self, name, age):
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self.name = name
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self.age = age
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def __repr__(self):
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return f'{self.name}: {self.age}'
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def main():
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# list1 = [12, 35, 48, 87, 92]
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# list2 = [39, 44, 50, 60, 77, 88]
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# list3 = merge(list1, list2)
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# print(list3)
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items = [34, 99, 52, 11, 47, 50, 84]
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print(items)
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print(merge_sort(items))
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# items = ['hi', 'hello', 'orange', 'watermelon', 'zoo', 'pitaya']
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# items = [
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# Person("LuoHao", 38), Person("Baiyuanfang", 25),
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# Person("Zhangsanfeng", 120), Person("Lee", 18)
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# ]
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# new_items = bubble_sort(items, comp=lambda x, y: len(x) > len(y))
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# new_items = bubble_sort(items, comp=lambda x, y: x.age > y.age)
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# print(items)
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# print(new_items)
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if __name__ == '__main__':
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main()
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