90. Subsets II

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90. Subsets II

Description

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:

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Input: nums = [1,2,2]
Output: [[],[1],[1,2],[1,2,2],[2],[2,2]]

Example 2:

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Input: nums = [0]
Output: [[],[0]]

Constraints:

  • 1 <= nums.length <= 10
  • -10 <= nums[i] <= 10

Hints/Notes

  • 2024/12/25
  • backtracking
  • No solution from 0x3F

Solution

Language: C++

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class Solution {
public:
    vector<vector<int>> res;
    vector<int> path;

    vector<vector<int>> subsetsWithDup(vector<int>& nums) {
        ranges::sort(nums);
        dfs(0, nums);
        return res;
    }

    void dfs(int index, vector<int>& nums) {
        if (index == nums.size()) {
            res.push_back(path);
            return;
        }
        path.push_back(nums[index]);
        dfs(index + 1, nums);
        path.pop_back();
        int start = index + 1;
        while (start < nums.size() && nums[start] == nums[index]) {
            start++;
        }
        dfs(start, nums);
    }
};