Given a collection of integers that might contain duplicates, 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 = [1,2,2]
, a solution is:
[ [2], [1], [1,2,2], [2,2], [1,2], [] ]
class Solution {
public:
vector<vector<int> > subsetsWithDup(vector<int> &S) {
vector<vector<int> > ret;
if(S.size() == 0) return ret;
sort(S.begin(), S.end());
vector<int> tmp;
dfs(S, 0, tmp, ret);
return ret;
}
void dfs(vector<int> &S, int beg, vector<int> tmp, vector<vector<int> > &ret) {
ret.push_back(tmp);
if(beg >= S.size()) return;
for(int i = beg; i < S.size(); ++i) {
if(i == beg || S[i] != S[i-1]) {
tmp.push_back(S[i]);
dfs(S, i+1, tmp, ret);
tmp.pop_back();
}
}
}
};
歡迎關注微信公衆號——計算機視覺: