LeetCode Permutaions II

LeetCode Permutaions II
LeetCode-solving Permutaions II

Original question

OutputRepeatedArray of numbers.

Note:

Duplicate numbers may cause repeated sorting

Example:

Input: nums = [1, 2, 1]
Output: [[1, 1, 2], [1, 2, 1], [2, 1, 1]

Solutions

This is the enhanced version of Permutations in the previous question. Now we need to consider repeated numbers. We adopt a lazy method to sort the array first, and ignore repeated numbers directly during the time, you only need to add two lines of code based on the original one.

AC Source Code

class Solution(object):    def permuteUnique(self, nums):        """        :type nums: List[int]        :rtype: List[List[int]]        """        result = []        nums.sort()        self.get_permute([], nums, result)        return result    def get_permute(self, current, num, result):        if not num:            result.append(current + [])            return        for i, v in enumerate(num):            if i - 1 >= 0 and num[i] == num[i - 1]:                continue            current.append(num[i])            self.get_permute(current, num[:i] + num[i + 1:], result)            current.pop()if __name__ == "__main__":    assert Solution().permuteUnique([1, 2, 1]) == [[1, 1, 2], [1, 2, 1], [2, 1, 1]]