# 全排列 II

<p>给定一个可包含重复数字的序列 <code>nums</code> ，<strong>按任意顺序</strong> 返回所有不重复的全排列。</p><p> </p><p><strong>示例 1：</strong></p><pre><strong>输入：</strong>nums = [1,1,2]<strong><br />输出：</strong>[[1,1,2], [1,2,1], [2,1,1]]</pre><p><strong>示例 2：</strong></p><pre><strong>输入：</strong>nums = [1,2,3]<strong><br />输出：</strong>[[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]</pre><p> </p><p><strong>提示：</strong></p><ul>	<li><code>1 <= nums.length <= 8</code></li>	<li><code>-10 <= nums[i] <= 10</code></li></ul>

## template

```java
class Solution {
	List<List<Integer>> ans = new ArrayList<>();

	public List<List<Integer>> permuteUnique(int[] nums) {
		dfs(nums, 0);
		return ans;
	}

	private void dfs(int[] nums, int cur) {
		if (cur == nums.length) {
			List<Integer> line = new ArrayList<>();
			for (int i : nums) {
				line.add(i);
			}
			ans.add(line);
		} else {
			for (int i = cur; i < nums.length; i++) {
				if (canSwap(nums, cur, i)) {
					swap(nums, cur, i);
					dfs(nums, cur + 1);
					swap(nums, cur, i);
				}
			}
		}
	}

	private boolean canSwap(int nums[], int begin, int end) {
		for (int i = begin; i < end; i++) {
			if (nums[i] == nums[end]) {
				return false;
			}
		}

		return true;
	}

	private void swap(int nums[], int i, int j) {
		int temp = nums[i];
		nums[i] = nums[j];
		nums[j] = temp;
	}
}
```

## 答案

```java

```

## 选项

### A

```java

```

### B

```java

```

### C

```java

```