#!/usr/bin/env python# -*- coding: <encoding name> -*- '''全排列的demoinput : 3output:123 132 213 231 312 321''' total = 0 def permutationCove(startIndex, n, numList): '''递归实现交换其中的两个。一直循环下去，直至startIndex == n ''' global total if startIndex >= n: total += 1 print numList return for item in range(startIndex, n): numList[startIndex], numList[item] = numList[item], numList[startIndex] permutationCove(startIndex + 1, n, numList ) numList[startIndex], numList[item] = numList[item], numList[startIndex] n = int(raw_input("please input your number:"))startIndex = 0total = 0numList = [x for x in range(1,n+1)]print '*' * 20for item in range(0, n): numList[startIndex], numList[item] = numList[item], numList[startIndex] permutationCove(startIndex + 1, n, numList) numList[startIndex], numList[item] = numList[item], numList[startIndex] print total 
