[Swift] Measure Set's contains() performance

main.swift

func time(title: String, execute: () -> ()) {
    let now = NSDate()
    execute()
    let interval = NSDate().timeIntervalSinceDate(now)
    print("\(title): \(interval)")
}

var s = Set<String>()
(0..<1000).forEach{ s.insert(String($0)) }

time("\(s.count) elements") {
    _ = s.contains("1")
}

(1000..<10000).forEach{ s.insert(String($0)) }

time("\(s.count) elements") {
    _ = s.contains("1")
}

(10000..<100000).forEach{ s.insert(String($0)) }

time("\(s.count) elements") {
    _ = s.contains("1")
}