1,刚刚被问懵了。我都害怕。请问如下代码中的count是不是记录了全部的次数。使用了一个全局变量count来记录比较的次数。争论的重点在于两个if是否要算入计数中。我认为这个属于开始执行和结束执行的条件。请教以下。
# -*- coding:utf-8 -*- import logging, copy """ 快速排序 """ def quicksort(mylist, first, last): if first < last: piovt = partition(mylist, first, last) quicksort(mylist, first, piovt-1) quicksort(mylist, piovt+1, last) return mylist, def partition(mylist, first, last): global count pivotValue = mylist[first] left = first + 1 right = last done = False while not done: count = count+1 while left <= right and mylist[left] <= pivotValue: count = count + 1 left = left + 1 while mylist[right] >= pivotValue and right >= left: count = count+1 right = right - 1 if right < left: done = True else: temp = mylist[left] mylist[left] = mylist[right] mylist[right] = temp temp = mylist[first] mylist[first] = mylist[right] mylist[right] = temp return right if __name__ == '__main__': count = 0 logging.basicConfig( level=logging.DEBUG, format='%(asctime)s-%(levelname)s => %(message)s') myListinit=[7,2,5,1,29,6,4,19,11] mylist = copy.deepcopy(myListinit) isIn = quicksort(mylist, 0, len(mylist)-1) if isIn : logging.debug( '\nbefore:%s\nafter:%s\n%d' %(myListinit, isIn, count))
你的代码是对的, if first < last: 不用加 这算是执行前的条件, if right < left:你上面已经加过一次 不管它进没进if