[LeetCode] 90. Subsets II

[LeetCode] 90. Subsets II

Given a collection of integers that might contain duplicates, nums, return all possible subsets.

Note: The solution set must not contain duplicate subsets.

For example,

If nums = [1,2,2], a solution is:

[

[2],

[1],

[1,2,2],

[2,2],

[1,2],

[]

]

与Subsets不同的是，有重复元素。

那就更换判断条件，push之前判断是否跟前一元素一样，一样就跳过，因为已经push过了。

class Solution {
public:
void getOneComb(vector<vector<int>>& ans, vector<int>& nums, int begin, int end, int k, vector<int>& res) {
if (res.size() == k) {
ans.push_back(res);
return;
}
for (int i=begin; i<end; ++i) {
if (i > begin && nums[i] == nums[i-1]) continue;
res.push_back(nums[i]);
getOneComb(ans, nums, i+1, end, k, res);
res.pop_back();
}
}

vector<vector<int>> subsetsWithDup(vector<int>& nums) {
sort(nums.begin(), nums.end());
vector<int> res;
vector<vector<int>> ans;
int begin = 0;
int end = nums.size();
int k=end;
for (int i=0; i<=k; ++i) {
getOneComb(ans, nums, begin, end, i, res);
}
return ans;
}
};