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1.冒泡排序 冒泡排序是一种交换排序。什么是交换排序呢？交换排序：两两比较待排序的关键字，并交换不满足次序要求的那对数，直到整个表都满足次序要求为止。 代码示例： def bubble_sort(demo:list): length = len(demo) for i in range(length): print("*"*30) for j in range(length-i-1): if demo[j] > demo[j+1]: demo[j],demo[j+1] = demo[j+1], demo[j] print('{}次:'.format(i),demo) print("最终排序：",demo) if __name__ == '__main__': num_list = [33, 4, 15, 2, 72, 57, 9, 52, 90, 55] bubble_sort(num_list)结果： ****************************** 0次: [4, 15, 2, 33, 57, 9, 52, 72, 55, 90] ****************************** 1次: [4, 2, 15, 33, 9, 52, 57, 55, 72, 90] ****************************** 2次: [2, 4, 15, 9, 33, 52, 55, 57, 72, 90] ****************************** 3次: [2, 4, 9, 15, 33, 52, 55, 57, 72, 90] ****************************** 4次: [2, 4, 9, 15, 33, 52, 55, 57, 72, 90] ****************************** 5次: [2, 4, 9, 15, 33, 52, 55, 57, 72, 90] ****************************** 6次: [2, 4, 9, 15, 33, 52, 55, 57, 72, 90] ****************************** 7次: [2, 4, 9, 15, 33, 52, 55, 57, 72, 90] ****************************** 8次: [2, 4, 9, 15, 33, 52, 55, 57, 72, 90] ****************************** 9次: [2, 4, 9, 15, 33, 52, 55, 57, 72, 90] 最终排序： [2, 4, 9, 15, 33, 52, 55, 57, 72, 90]从结果中看出，其实在第3次时，就已经完成了排序，之后的迭代只是在浪费时间，所以可以优化下。代码示例： def bubble_sort(demo:list): length = len(demo) for i in range(length): flag = False print("*"*30) for j in range(length-i-1): if demo[j] > demo[j+1]: demo[j],demo[j+1] = demo[j+1], demo[j] flag = True print('{}次:'.format(i), demo) if not flag: break print("最终排序：",demo) if __name__ == '__main__': num_list = [33, 4, 15, 2, 72, 57, 9, 52, 90, 55] bubble_sort(num_list)结果 ****************************** 1次: [4, 2, 15, 33, 9, 52, 57, 55, 72, 90] ****************************** 2次: [2, 4, 15, 9, 33, 52, 55, 57, 72, 90] ****************************** 3次: [2, 4, 9, 15, 33, 52, 55, 57, 72, 90] 最终排序： [2, 4, 9, 15, 33, 52, 55, 57, 72, 90]2.直接排序原理：在未排序序列中，构建一个子排序序列，直至全部数据排序完成。将待排序的数，插入到已经排序的序列中合适的位置。增加一个哨兵，放入待比较值，让它和后面已经排序好的序列比较，找到合适的插入点。 代码示例 def insert_sort(li): for i in range(1,len(li)): tmp = li[i] j = i-1 while j>=0 and li[j]>tmp: li[j+1] = li[j] j-=1 li[j+1] = tmp print(f"{i}:{li}") print(li) if __name__ == '__main__': li = [33, 4, 15, 2, 72, 57, 9, 52, 90, 55] insert_sort(li)结果: 1:[4, 33, 15, 2, 72, 57, 9, 52, 90, 55] 2:[4, 15, 33, 2, 72, 57, 9, 52, 90, 55] 3:[2, 4, 15, 33, 72, 57, 9, 52, 90, 55] 4:[2, 4, 15, 33, 72, 57, 9, 52, 90, 55] 5:[2, 4, 15, 33, 57, 72, 9, 52, 90, 55] 6:[2, 4, 9, 15, 33, 57, 72, 52, 90, 55] 7:[2, 4, 9, 15, 33, 52, 57, 72, 90, 55] 8:[2, 4, 9, 15, 33, 52, 57, 72, 90, 55] 9:[2, 4, 9, 15, 33, 52, 55, 57, 72, 90] [2, 4, 9, 15, 33, 52, 55, 57, 72, 90]3.简单选择排序简单选择排序是一种选择排序。选择排序：每趟从待排序的记录中选出关键字最小的记录，顺序放在已排序的记录序列末尾，直到全部排序结束为止。 代码示例 def simple_select_sort1(demo:list): """ 简单选择排序 :param demo: :return: """ length = len(demo) for i in range(length): maxindex = i for j in range(i + 1, length): if demo[maxindex] < demo[j]: maxindex = j if i != maxindex: demo[i], demo[maxindex] = demo[maxindex], demo[i] print("{}次{}".format(i, demo)) print("最终排序".format(demo)) def simple_select_sort2(demo:list): """ 优化后简单选择排序 :param demo: :return: """ length = len(demo) for i in range(length // 2): maxindex = i minindex = -i - 1 minorgin = minindex for j in range(i + 1, length - i): if demo[maxindex] < demo[j]: maxindex = j if demo[minindex] > demo[-j - 1]: minindex = -j - 1 if i != maxindex: demo[i], demo[maxindex] = demo[maxindex], demo[i] if i == length + minindex: minindex = maxindex if minorgin != minindex: demo[minorgin], demo[minindex] = demo[minindex], demo[minorgin] print("{}次{}".format(i, demo)) print("最终排序{}".format(demo)) if __name__ == '__main__': num_list = [33, 4, 15, 2, 72, 57, 9, 52, 90, 55] simple_select_sort1(num_list) print("*" * 40) simple_select_sort2(num_list)结果 0次[90, 4, 15, 2, 72, 57, 9, 52, 33, 55] 1次[90, 72, 15, 2, 4, 57, 9, 52, 33, 55] 2次[90, 72, 57, 2, 4, 15, 9, 52, 33, 55] 3次[90, 72, 57, 55, 4, 15, 9, 52, 33, 2] 4次[90, 72, 57, 55, 52, 15, 9, 4, 33, 2] 5次[90, 72, 57, 55, 52, 33, 9, 4, 15, 2] 6次[90, 72, 57, 55, 52, 33, 15, 4, 9, 2] 7次[90, 72, 57, 55, 52, 33, 15, 9, 4, 2] 8次[90, 72, 57, 55, 52, 33, 15, 9, 4, 2] 9次[90, 72, 57, 55, 52, 33, 15, 9, 4, 2] 最终排序 **************************************** 0次[90, 72, 57, 55, 52, 33, 15, 9, 4, 2] 1次[90, 72, 57, 55, 52, 33, 15, 9, 4, 2] 2次[90, 72, 57, 55, 52, 33, 15, 9, 4, 2] 3次[90, 72, 57, 55, 52, 33, 15, 9, 4, 2] 4次[90, 72, 57, 55, 52, 33, 15, 9, 4, 2] 最终排序[90, 72, 57, 55, 52, 33, 15, 9, 4, 2] |
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