permutation dfs

gistfile1.py

# !/usr/bin/python
# -*- encoding: utf-8 -*-

string_list = ['a', 'b', 'c', 'd', 'e']
used = [0, 0, 0, 0, 0]
def dfs_permutation(permu, l):
    if l == 3:
        print permu
    for i in range(len(string_list)):
        if 0 == used[i]:
            used[i] = 1
            dfs_permutation(permu + string_list[i], l + 1)
            used[i] = 0
dfs_permutation('', 0)