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# [47. Permutations II](https://leetcode.com/problems/permutations-ii/)
## 题目
Given a collection of numbers that might contain duplicates, return all possible unique permutations.
**Example:**
Input: [1,1,2]
Output:
[
[1,1,2],
[1,2,1],
[2,1,1]
]
## 题目大意
给定一个可包含重复数字的序列,返回所有不重复的全排列。
## 解题思路
- 这一题是第 46 题的加强版,第 46 题中求数组的排列,数组中元素不重复,但是这一题中,数组元素会重复,所以需要最终排列出来的结果需要去重。
- 去重的方法是经典逻辑,将数组排序以后,判断重复元素再做逻辑判断。
- 其他思路和第 46 题完全一致DFS 深搜即可。