Python实现全排列的打印

#!/usr/bin/env python
# -*- coding: <encoding name> -*- 
'''
全排列的demo
input : 3
output: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 = 0
total = 0
numList = [x for x in range(1,n+1)]
print '*' * 20
for 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