全排列（字符串与列表）Python代码

字符串的全排列

输出参数是字符串，输出值为列表

def permutation(str):
    lenstr = len(str)
    if lenstr < 2:
        return str
    else:
        result = []
        for i in range(lenstr):
            ch = str[i]
            rest = str[0:i] + str[i + 1:lenstr]
            for s in permutation(rest):
                result.append(ch + s)  # 将ch与子问题的解依次组合
    return result


print(permutation('ab'))

输出
$['ab', 'ba']$

列表数字的全排列

def permutation(nums, p, q):
    if p == q:
        s.append(list(nums))
    else:
        for i in range(p, q):
            nums[i], nums[p] = nums[p], nums[i]
            permutation(nums, p + 1, q)
            nums[i], nums[p] = nums[p], nums[i]


s = []
nums = [i for i in range(1, 4)]
permutation(nums, 0, len(nums))
print(s)

输出
$[[1, 2, 3], [1, 3, 2], [2, 1, 3], [2, 3, 1], [3, 2, 1], [3, 1, 2]]$