3.swift

import Foundation

func solution(_ n:Int) -> Int {
	let sorted_n = "\(n)".sorted()
	let i = Int(pow(Double(10), Double("\(n)".count)))
	return Array(0...i).filter { "\($0)".sorted() == sorted_n }.count
}

print(solution(0))
print(solution(1))
print(solution(2))
print(solution(123))
print(solution(1132))
print(solution(99998))