[Swift] 백준! 2981번 - 검문

https://www.acmicpc.net/problem/2981

2981번: 검문

import Foundation

func gcd(_ a: Int, _ b: Int) -> Int{
    if (b == 0) { return a }
    return gcd(b, a % b)
}

let n = Int(readLine()!)!
var l:[Int] = []
var minv = 1000000000
for _ in 1...n {
    let num = Int(readLine()!)!
    l.append(num)
    if num < minv {
        minv = num
    }
}

var str = ""
var v = l[0]-minv
for i in 1...l.count-1 {
    if l[i] > minv {
        v = gcd(v, l[i]-minv)
    }
}

if v > 3 {
    for i in 2...v/2 {
        if v%i == 0 {
            if str == "" {
                str += "\(i)"
            } else {
                str += " \(i)"
            }
        }
    }
}
if str == "" {
    str += "\(v)"
} else {
    str += " \(v)"
}

print(str)