LeetCode--Subsets

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],

[]

]

思路：深度优先搜索。这一题和上一题类似，不同在于扩展后1到n个数都要进行组合，还有要注意先添加一个空数组，而且不再是1到n的连续数字，可能是不同数字组成的数组。

class Solution {
public:
vector<vector<int>> subsets(vector<int>& nums) {
vector<vector<int>>result;
vector<int>path;
result.push_back(path);
for(int i=1;i<=nums.size();i++){
dfs(result,path,nums,i,0);
}
return result;
}
void dfs(vector<vector<int>>&result,vector<int>&path,vector<int>&nums,int k,int start){
if(path.size()==k){
result.push_back(path);
return;
}
for(int i=start;i<nums.size();i++){
path.push_back(nums[i]);
dfs(result,path,nums,k,i+1);
path.pop_back();
}
}
};