// 2215. Find the Difference of Two Arrays

func findDifference(_ nums1: [Int], _ nums2: [Int]) -> [[Int]] {
    let setOne = Set(nums1)
    let setTwo = Set(nums2)

    var firstNo = Set<Int>()
    var secondNo = Set<Int>()

    for num in setOne {

        if !setTwo.contains(num) {
            firstNo.insert(num)
        }
    }

    for num in setTwo {
        if !setOne.contains(num) {
            secondNo.insert(num)
        }
    }
    return [Array(firstNo), Array(secondNo)]
}