LeetCode-in-All

78. Subsets

Medium

Given an integer array nums of unique elements, 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 = [1,2,3]

Output: [[],[1],[2],[1,2],[3],[1,3],[2,3],[1,2,3]]

Example 2:

Input: nums = [0]

Output: [[],[0]]

Constraints:

Solution

object Solution {
    def subsets(nums: Array[Int]): List[List[Int]] = {
        val res = new scala.collection.mutable.ListBuffer[List[Int]]
        solve(nums, List.empty[Int], res, 0)
        res.toList
    }

    private def solve(nums: Array[Int], temp: List[Int], res: scala.collection.mutable.ListBuffer[List[Int]], start: Int): Unit = {
        res += temp
        for (i <- start until nums.length) {
            solve(nums, nums(i) :: temp, res, i + 1)
        }
    }
}