LeetCode in Kotlin

90. Subsets II

Medium

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:

Solution

class Solution {
    private var allComb: MutableList<List<Int>> = ArrayList()
    private var comb: MutableList<Int> = ArrayList()
    private lateinit var nums: IntArray

    fun subsetsWithDup(nums: IntArray): List<List<Int>> {
        nums.sort()
        this.nums = nums
        dfs(0)
        allComb.add(ArrayList())
        return allComb
    }

    private fun dfs(start: Int) {
        if (start > nums.size) {
            return
        }
        for (i in start until nums.size) {
            if (i > start && nums[i] == nums[i - 1]) {
                continue
            }
            comb.add(nums[i])
            allComb.add(ArrayList(comb))
            dfs(i + 1)
            comb.removeAt(comb.size - 1)
        }
    }
}