题解 | #没有重复项数字的全排列#

#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# @param num int整型一维数组 
# @return int整型二维数组
#
class Solution:
    def permute(self , num: List[int]) -> List[List[int]]:
        if len(num) <= 1: return [num]
        a = num[0]
        result = self.permute(num[1:])
        new_result = []
        for i in range(len(result)):
            tmp = result[i]
            new_result.append([a] + tmp)
            new_result.append(tmp + [a])
            for j in range(len(tmp)-1):
                new_result.append(tmp[:j+1] + [a] + tmp[j+1:])
        return new_result