Solution to problem 2 from "5 Programming Problems, 1 Hour"

problem_2_of_5.swift

//: Problem 2
//  "Write a function that combines two lists by alternatingly taking elements. For example: given the two lists [a, b, c] and [1, 2, 3], the function should return [a, 1, b, 2, c, 3]."
//  https://www.shiftedup.com/2015/05/07/five-programming-problems-every-software-engineer-should-be-able-to-solve-in-less-than-1-hour

//  Xcode 7.0, Swift 2.0

//  Assumption: homogeneous arrays, same length


let first = ["a", "b", "c"]
let second = ["1", "2", "3"]
let result = ["a", "1", "b", "2", "c", "3"]

func combine<T>(first: [T], second: [T]) -> [T] {
    var result = [T]()
    
    for i in (0..<first.count) {
        result.append(first[i])
        result.append(second[i])
    }
    
    return result
}

assert(result == combine(first, second: second))