一、题目内容

二、题解

解法1：

思路

代码

public class Solution {
    ArrayList<ArrayList<Integer>> ans;
    LinkedList<Integer> path = new LinkedList<>();
    int[] nums;
    public ArrayList<ArrayList<Integer>> permute(int[] num) {
        ans = new ArrayList();
        path = new LinkedList<>();
        this.nums = num;
        recur();
        return ans;
    }
    private void recur(){
        if(path.size() == nums.length){
            ans.add(new ArrayList(path));
            return;
        }
        for(int i = 0;i<nums.length;i++){
            if(path.contains(nums[i])){
                continue;
            }
            path.add(nums[i]);
            recur();
            path.removeLast();
        }
    }
}