Swift Subsets Algorithm: Generating All Subsets of an Array

class Solution { var t = Int var ans = [Int]

func subsets(_ nums: [Int]) -> [[Int]] {
    let n = nums.count
    for mask in 0..<(1 << n) {
        t.removeAll()
        for i in 0..<n {
            if (mask & (1 << i)) != 0 {
                t.append(nums[i])
            }
        }
        ans.append(t)
    }
    return ans
}

}