# 全排列 II
给定一个可包含重复数字的序列 nums ，按任意顺序 返回所有不重复的全排列。
示例 1：
输入：nums = [1,1,2]
输出：[[1,1,2], [1,2,1], [2,1,1]]
示例 2：
输入：nums = [1,2,3]
输出：[[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
提示：
1 <= nums.length <= 8-10 <= nums[i] <= 10
## template
```cpp
#include
using namespace std;
class Solution
{
public:
vector> permuteUnique(vector &nums)
{
vector> res;
vector used(nums.size());
sort(nums.begin(), nums.end());
dfs(nums, used, res);
return res;
}
private:
vector stack;
void dfs(vector &nums, vector &used, vector> &res)
{
if (stack.size() == nums.size())
{
res.push_back(stack);
}
else
{
for (int i = 0; i < nums.size(); i++)
{
if (!used[i])
{
if (i > 0 && !used[i - 1] && nums[i - 1] == nums[i])
{
continue;
}
stack.push_back(nums[i]);
used[i] = true;
dfs(nums, used, res);
stack.pop_back();
used[i] = false;
}
}
}
}
};
```
## 答案
```cpp
```
## 选项
### A
```cpp
```
### B
```cpp
```
### C
```cpp
```