sumBetweenTwoIntegers.swift

import Foundation

func solution(_ a:Int, _ b:Int) -> Int64 {
    var result = 0
    let max: Int
    let min: Int
    
    if a > b {
        max = a
        min = b
    } else {
        max = b
        min = a
    }
        
    for number in min...max {
        result += number
    }
    
    return Int64(result)
}