Posted in Python onMarch 04, 2013
# -*- coding: utf-8 -*- # 测试各种排序算法 # link:3water.com # date:2013/2/2 #选择排序 def select_sort(sort_array): for i, elem in enumerate(sort_array): for j, elem in enumerate(sort_array[i:]): if sort_array[i] > sort_array[j + i]: #交换 sort_array[i], sort_array[j + i] = sort_array[j + i], sort_array[i] #冒泡排序 def bubble_sort(sort_array): for i, elem in enumerate(sort_array): for j, elem in enumerate(sort_array[:len(sort_array) - i - 1]): if sort_array[j] > sort_array[j + 1]: sort_array[j], sort_array[j + 1] = sort_array[j + 1], sort_array[j] #插入排序 def insert_sort(sort_array): for i, elem in enumerate(sort_array): for j, elem in enumerate(sort_array[:i]): if sort_array[j] > sort_array[i]: sort_array.insert(j, sort_array[i]) del sort_array[i + 1] #归并排序 def merge_sort_wrapper(sort_array): merge_sort(sort_array, 0, len(sort_array) - 1) def merge_sort(sort_array, left = 0, right = 0): if left < right: center = (left + right) / 2 merge_sort(sort_array, left, center) merge_sort(sort_array, center + 1, right) merge(sort_array, left, right, center) def merge(sort_array, left, right, center): result = [] arrayA = sort_array[left:center + 1] arrayB = sort_array[center + 1:right + 1] while((len(arrayA) > 0) and (len(arrayB) > 0)): if(arrayA[0] > arrayB[0]): result.append(arrayB.pop(0)) else: result.append(arrayA.pop(0)) if(len(arrayA) > 0): result.extend(arrayA) if(len(arrayB) > 0): result.extend(arrayB) sort_array[left:right + 1] = result #快排 def quick_sort(sort_array): if(len(sort_array) < 2): return left = [x for x in sort_array[1:] if x < sort_array[0]] right = [x for x in sort_array[1:] if x >= sort_array[0]] quick_sort(left) quick_sort(right) sort_array[:] = left + [sort_array[0]] + right #shell排序 def shell_sort(sort_array): dist=len(sort_array)/2 while dist > 0: for i in range(dist,len(sort_array)): tmp=sort_array[i] j = i while j >= dist and tmp < sort_array[j - dist]: sort_array[j] = sort_array[j - dist] j -= dist sort_array[j] = tmp dist /= 2 #基数排序,均为整数,不支持负数和重复 def radix_sort(sort_array): max_elem = max(sort_array) bucket_list = [] for i in range(max_elem): bucket_list.insert(i, 0) for x in sort_array: bucket_list[x - 1] = -1 sort_array[:] = [x + 1 for x in range(len(bucket_list)) if bucket_list[x] == -1] #堆排序 def heap_sort(sort_array): #没有写出来,再想想 pass #测试例子 def algo_sort_test(sort_array, sort_method): sort_method(sort_array) if __name__ == '__main__': sort_array = [1, 2, 3, 5, -4, 4, 10, 3, 19, 13, 16, 18, 5, 190, 456, 23] algo_sort_test(sort_array, select_sort) print sort_array sort_array = [1, 2, 3, 5, -4, 4, 10, 3, 19, 13, 16, 18, 5, 190, 456, 23] algo_sort_test(sort_array, bubble_sort) print sort_array sort_array = [1, 2, 3, 5, -4, 4, 10, 3, 19, 13, 16, 18, 5, 190, 456, 23] algo_sort_test(sort_array, insert_sort) print sort_array sort_array = [1, 2, 3, 5, -4, 4, 10, 3, 19, 13, 16, 18, 5, 190, 456, 23] algo_sort_test(sort_array, merge_sort_wrapper) print sort_array sort_array = [1, 2, 3, 5, -4, 4, 10, 300, 19, 13, 16, 18, 500, 190, 456, 23] algo_sort_test(sort_array, quick_sort) print sort_array sort_array = [1, 2, 3, 5, -4, 4, 10, 3, 19, 13, 16, 18, 5, 190, 456, 23] algo_sort_test(sort_array, shell_sort) print sort_array sort_array = [1, 2, 3, 5, 4, 10, 19, 13, 16, 18, 190, 456, 23] algo_sort_test(sort_array, radix_sort) print sort_array print 'OK'
非常基础的知识内容,选择、冒泡、插入、归并、基数,还有快排都能手写出来,但写了一遍发现堆排序忘了怎么做了。要复习啦。
python实现的各种排序算法代码
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