Leetcode: 78. Subsets

Description

Given a set of distinct integers, nums, return all possible subsets.

Note: The solution set must not contain duplicate subsets.

Example

If nums = [1,2,3], a solution is:

[
    [3],
    [1],
    [2],
    [1,2,3],
    [1,3],
    [2,3],
    [1,2],
    []
]

思路

• 常规的回溯

代码

class Solution {
public:
    vector<vector<int>> subsets(vector<int>& nums) {
        vector<vector<int>> res;
        vector<int> vec;
        getResult(res, vec, nums, 0);
        
        return res;
    }
    
    void getResult(vector<vector<int>>& res, vector<int>&vec, 
            vector<int>& nums, int t){
    
        res.push_back(vec);
        
        for(int i = t; i < nums.size(); ++i){
            vec.push_back(nums[i]);
            getResult(res, vec, nums, i + 1);
            vec.pop_back();
        }
    }
};