[Leetcode]Subsets

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

Note:

Elements in a subset must be in non-descending order.
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],
[]
]

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

sort(nums.begin(),nums.end());
dfs(result,path,0,nums);
return result;
}
};

class Solution {
public:
/*algorithm
iterate from [],
*/
vector<vector<int>> subsets(vector<int>& nums) {
vector<vector<int>>result;

sort(nums.begin(),nums.end());
result.push_back(vector<int>());//add []
for(int i = 0;i < nums.size();i++){
int size = result.size();
for(int k = 0;k < size;k++){
vector<int>copy(result[k].begin(),result[k].end());
copy.push_back(nums[i]);
result.push_back(copy);
}
}
return result;
}
};