[leetcode]Subsets II

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],
[]
]

这个曾经让我很捉鸡的题目。。。为什么这次用了个很烂的dfs，一次性通过，而且是80ms过大集合。。。。太讽刺了。。。

class Solution {
set<vector<int>> result;
public:
void dfs(vector<int>&S, int i, vector<int> tmp){
if(i == S.size()){
sort(tmp.begin(), tmp.end());
result.insert(tmp);
return;
}
dfs(S, i+1, tmp);

tmp.push_back(S[i]);
dfs(S, i+1, tmp);

}

vector<vector<int> > subsetsWithDup(vector<int> &S) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
result.clear();
vector<int> tmp;
dfs(S, 0, tmp);
set<vector<int>>::iterator it;

vector<vector<int>> ret;
for(it = result.begin(); it!=result.end(); it++){
ret.push_back(*it);
}

return ret;

}
};