gistfile1.txt

import Foundation

func sockMerchant(n: Int, ar: [Int]) -> Int {

    //check if the amount of socks is valid
    if n < 1 || n > 100 {
        print("Please, enter a valid array (1 to 100 items).")
        return 0
    }

    let result = findPairs(ar: ar, pairs: 0)
    print(result)
    return result
}

func findPairs(ar: [Int], pairs: Int) -> Int {
    
    var res = pairs
    
    if ar.count > 0 {

        var newAr = ar

        let sock = newAr.remove(at: 0)

        for (index, element) in newAr.enumerated() {
        
            if element == sock {
                
                newAr.remove(at: index)
                res += 1
                break
            }
        }
        
        return findPairs(ar: newAr, pairs: res)
    }
    
    return res
}



sockMerchant(n: 7, ar: [1,2,3,4,1,5,2])