1 Description #
source: https://leetcode.com/problems/subsets-ii/
Given an integer array nums that may contain duplicates, return all possible subsets (the power set).
The solution set must not contain duplicate subsets. Return the solution in any order.
Example 1:
Input: nums = [1,2,2]
Output: [[],[1],[1,2],[1,2,2],[2],[2,2]]
Example 2:
Input: nums = [0]
Output: [[],[0]]
Constraints:
1 <= nums.length <= 10-10 <= nums[i] <= 10
2 Solution #
#include <algorithm>
class Solution {
public:
vector<vector<int>> subsetsWithDup(vector<int>& nums) {
// Time complexity: O(N!), N is the size of nums
// Space complexity: O(N!)
std::vector<std::vector<int>> result;
std::vector<int> path;
std::sort(nums.begin(), nums.end());
backtrack(nums, 0, result, path);
return result;
}
private:
void backtrack(const std::vector<int>& nums, int start, std::vector<std::vector<int>>& result, std::vector<int>& path){
result.push_back(path);
for(int i = start; i < nums.size(); i++){
// skip duplicate
if(i > start && nums[i] == nums[i - 1]){
continue;
}
path.push_back(nums[i]);
backtrack(nums, i + 1, result, path);
path.pop_back();
}
}
};