The topic of the law back Leetcode -78. Subset (Subsets)

The topic of the law back Leetcode -78. Subset (Subsets)

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Given a set of integer array elements no repeating  the nums , which returns an array of all possible subsets (power set).

Description: Solution Set can not contain duplicate subsets.

Example:

Input: nums = [1,2,3] 
Output: 
[ 
  [3], 
  [1], 
  [2], 
  [2,3], 
  [1,3], 
  [2,3], 
  [1,2 ], 
  [] 
]

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Analysis: 
This question is about a very basic question of backtracking, to an array of questions, ask him subset (including the empty set). 

AC Code:

class Solution {
    
    List<List<Integer>> ans = new ArrayList<>();
    public List<List<Integer>> subsets(int[] nums) {
        int[] vis = new int[nums.length];
        
        dfs(nums,new ArrayList<Integer>(),0);
        return ans;
    }
    public void dfs(int nums[],ArrayList<Integer> list,int step){
        
        if(step==nums.length){
            ans.add(new ArrayList<>(list));
            return;
        }
        
        list.add(nums[step]);
        dfs(nums,list,step+1);
        list.remove(list.size()-1);
        dfs(nums,list,step+1);
        
    }
}