leetcode 全排列

 

 

很正常的DFS深度遍历或者暴力递归也可以。

class Solution {
     List<List<Integer>>  res=new LinkedList<>();
    public List<List<Integer>> permute(int[] nums) { 
         LinkedList<Integer> track=new LinkedList<>();
         dfs(nums,track);
         return res;
    }
    public void dfs(int [] nums,LinkedList<Integer> track)
    {
        if(nums.length==track.size())
        {
            res.add(new LinkedList(track));
            return;
        }

        for(int i=0;i<nums.length;i++)
        {
            if(track.contains(nums[i]))
                continue;
            track.add(nums[i]);
            dfs(nums,track);
            track.removeLast();
        }
    }
}