LeetCode - 78 - Subsets（求数组全部子集）

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],
[]
]

求一个数组的所有子集，dfs一遍

class Solution {
public:
vector<vector<int>> subsets(vector<int>& nums) {
vector<vector<int> > ans;
if (nums.empty()) return ans;
vector<bool> vis(nums.size(), false);
dfs(nums, ans, vis, 0);
return ans;

}
void dfs(vector<int> nums, vector<vector<int> >& ans, vector<bool>& vis, int loc) {
if (loc == nums.size()) {
vector<int> mie;
for (int i = 0; i < nums.size(); ++i) {
if (vis[i]) mie.push_back(nums[i]);
}
ans.push_back(mie);
return;
}

dfs(nums, ans, vis, loc+1);
vis[loc] = true;
dfs(nums, ans, vis, loc+1);
vis[loc] = false;
return;
}
};