gistfile1.txt

Assumptions: 

I don't have any assumptions. The instructions were pretty straightforward.

Test Cases:

[0, 1, 2, 3]
[2, 2, 3, 3, 2]
[]

Implementation:

First I will guard against an empty array. The function will return nil if the array is empty.The I will loop through the
with a for loop, hopefully use a built-in method to check for number of elements for each index, and then use a modulo to see
if it is divisible by 0. If it is then I will return the first index found with an even amount of occurences.

Code:

import UIKit

func evenOccurence(array: [Int]) -> Int? {
    if array == [] {
        return nil
    }
    var count = 1
    var otherArray = array
    otherArray.removeFirst()
    var newArray: [Int] = [otherArray[0]]
    
    newArray = [otherArray[0]]
    for index in array {
        if newArray.contains(index) && otherArray.count > 0 {
            
            newArray += [index]
            otherArray.removeFirst()
            count += 1
        }
    
}
    print(newArray)
    return count
}
evenOccurence(array: [8,9,9, 8, 9, 8, 9])