04
08/2015
[LeetCode] Subsets II
Subsets II
Given a collection of integers that might contain duplicates, nums, 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 nums = [1,2,2], a solution is:
[ [2], [1], [1,2,2], [2,2], [1,2], [] ]
解题思路：
去重的话用一个set来记录。枚举的话，可以二进制递增来枚举。i从0递增到2^n-1，若i的二进制表示中，相应位为1，则添加到项中。
class Solution {
public:
vector<vector<int>> subsetsWithDup(vector<int>& nums) {
vector<vector<int>> result;
set<vector<int>> contains; //已经包含的
std::sort(nums.begin(), nums.end());
int num = 1 << nums.size();
for(int i=0; i<num; i++){
int flag = i;
int j=0;
vector<int> item;
while(flag!=0){
if(flag&0x1==1){
item.push_back(nums[j]);
}
flag = flag>>1;
j++;
}
if(contains.find(item)==contains.end()){
contains.insert(item);
result.push_back(item);
}
}
return result;
}
};转载请注明：康瑞部落 » [LeetCode] Subsets II
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