FindMissingNumbers

FindMissingNumbers.swift

func findMissingNumbers(_ nums: [Int]) -> [Int] {
    var includedNums = [Int:Int]()
    var missingNums = [Int]()
    
    for num in nums {
        includedNums[num] = num
    }
    
    for i in 1...nums.count {
        if includedNums[i] == nil {
            missingNums.append(i)
        }
    }
    
    return missingNums
}

print(findMissingNumbers([4,3,2,7,8,2,3,1]))
print(findMissingNumbers([1,9,9,6,1,2,3,4,5,5,5]))