78. Subsets

78. Subsets

题目：

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

Note: The solution set must not contain duplicate subsets.

For example :

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

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

代码如下：

class Solution {
public:
    vector<vector<int>> subsets(vector<int>& nums) {
        sort(nums.begin(), nums.end());
        vector<vector<int>> subs;
        vector<int> sub;  
        genSubsets(nums, 0, sub, subs);
        return subs; 
    }
    void genSubsets(vector<int>& nums, int start, vector<int>& sub, vector<vector<int>>& subs) {
        subs.push_back(sub);
        for (int i = start; i < nums.size(); i++) {
            sub.push_back(nums[i]);
            genSubsets(nums, i + 1, sub, subs);
            sub.pop_back();
        }
    }
};