SubsetsApr 18 '126226 / 16269
Given a set of distinct integers, S, 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 S = [1,2,3], a solution is:
[ [3], [1], [2], [1,2,3], [1,3], [2,3], [1,2], [] ]
class Solution {
public:
vector<vector<int> > subsets(vector<int> &S) {
sort(S.begin(), S.end());
vector<vector<int> > res;
int n = S.size();
for (int i = 0; i <= n; i++) {
vector<int> a;
gen(res, S, i, 0, a);
}
return res;
}
void gen(vector<vector<int> >& res, const vector<int>& s, int n, int cur, vector<int> &a) {
if (a.size() == n) {
res.push_back(a);
return;
}
if (cur == s.size()) return;
gen(res, s, n, cur+1, a);
a.push_back(s[cur]);
gen(res, s, n, cur+1, a);
a.pop_back();
}
};