78. Subsets

Medium

Given an integer array nums of unique elements, return all possible subsets¹ (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:

• 1 <= nums.length <= 10
• -10 <= nums[i] <= 10
• All the numbers of nums are unique.

Solution:

class Solution {

    /**
     * @param Integer[] $nums
     * @return Integer[][]
     */
    function subsets($nums) {
        $ans = [[]];    
        foreach($nums as $num){
            $ans_size = count($ans);            
            for($i = 0; $i < $ans_size; $i++){
                $cur = $ans[$i];
                $cur[] = $num;
                $ans[] = $cur;
            }
        }        
        return $ans;
    }
}

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1. Subset A subset of an array is a selection of elements (possibly none) of the array. ↩