Implement full permutation in Python

| Dec 11, 2014 | Algorithm python

算法题，利用Python实现一个全排列算法。要求：

1. 实现一个递归的全排列算法
2. 在1的基础上加上去重功能（有bug）
3. 实现一个非递归的全排列算法（未实现）

代码如下：

def permutation(operate_list, m, n):
    if m == n-1:
        print operate_list
        return
    else:
        for i in range(m, n):
            operate_list[m], operate_list[i] = operate_list[i], operate_list[m]
            permutation(operate_list, m+1, n)
            operate_list[m], operate_list[i] = operate_list[i], operate_list[m]

def deduplicated_permutation(operate_list, m, n):
    if m == n-1:
        print operate_list
        return
    else:
        for i in range(m, n):
            if is_swap(operate_list, m, i):
                operate_list[m], operate_list[i] = operate_list[i], operate_list[m]
                permutation(operate_list, m+1, n)
                operate_list[m], operate_list[i] = operate_list[i], operate_list[m]

# FIXME BUG
def is_swap(operate_list, m, n):
    for i in range(m, n):
       if operate_list[i] == operate_list[n]:
            return False
    return True


if __name__ == '__main__':
    test = ['a', 'b', 'c', 'd']
    permutation(test, 0, 4)

    test_duplicate = ['a', 'c', 'c']
    deduplicated_permutation(test_duplicate, 0, 3)