def permutate(s): if not s: return [s] r = [] for i in range(len(s)): for m in permutate(s[:i] + s[i+1:]): r.append(s[i:i+1] + m) return r
字母各异的全排列
原文：http://www.cnblogs.com/LyningCoder/p/4299551.html
