# ---
# title: 47. Permutations II
# id: problem47
# author: Tian Jun
# date: 2020-10-31
# difficulty: Medium
# categories: Backtracking
# link: <https://leetcode.com/problems/permutations-ii/description/>
# hidden: true
# ---
# 
# Given a collection of numbers, `nums`, that might contain duplicates, return
# _all possible unique permutations **in any order**._
# 
# 
# 
# **Example 1:**
# 
#     
#     
#     Input: nums = [1,1,2]
#     Output:
#     [[1,1,2],
#      [1,2,1],
#      [2,1,1]]
#     
# 
# **Example 2:**
# 
#     
#     
#     Input: nums = [1,2,3]
#     Output: [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
#     
# 
# 
# 
# **Constraints:**
# 
#   * `1 <= nums.length <= 8`
#   * `-10 <= nums[i] <= 10`
# 
# 
## @lc code=start
using LeetCode

## add your code here:
## @lc code=end
