一、题目内容

二、题解

解法1：

思路

boolean visited[]

代码

public class Solution {
    ArrayList<ArrayList<Integer>> ans = new ArrayList<>();
    ArrayList<Integer> tempAns = new ArrayList<>();
    boolean[] visited;
    public ArrayList<ArrayList<Integer>> permuteUnique(int[] num) {
        Arrays.sort(num);
        visited = new boolean[num.length];
        recur(num, 0);
        return ans;
    }
    private void recur(int[] num,int count){
        if(count == num.length){
            ans.add(new ArrayList(tempAns));
            return;
        }
        for(int i = 0;i<num.length;i++){
            if(i>0&&!visited[i]&&!visited[i-1]&&num[i] == num[i-1]){
                continue;
            }
            if(!visited[i]){
                visited[i] = true;
                tempAns.add(num[i]);
                recur(num,count+1);
                visited[i] = false;
                tempAns.remove(tempAns.size()-1);
            }
        }
    }
}