[LeetCode] 78. Subsets

void dfs(vector<vector<int>>& res, vector<int>& candidate, vector<int>& nums, int start) {
res.push_back(candidate);
for (int i = start; i < nums.size(); i++) {
candidate.push_back(nums[i]);
dfs(res, candidate, nums, i + 1);
candidate.pop_back();
}
}
vector<vector<int>> subsets(vector<int>& nums) {
vector<vector<int>> res;
vector<int> candidate;

sort(nums.begin(), nums.end());
dfs(res, candidate, nums, 0);
return res;
}

vector<vector<int>> subsets(vector<int>& nums) {
vector<vector<int>> res(1, vector<int>());

sort(nums.begin(), nums.end());
for (int i = 0; i < nums.size(); i++) {
int n = res.size();
for (int j = 0; j < n; j++) {
res.push_back(res[j]);
res.back().push_back(nums[i]);
}
}

return res;
}