NSScanner Example: Fast Data parsing using swift

FastParsing.swift

// Use by piping
// cat input22.txt | ./MyScanner

// This is very slow
// let xy = (readLine()!).characters.split(" ").map{Int(String($0))!}

import Foundation

var str = ""
while true {
    guard let input = readLine() else {
        break
    }
    str += input
}

// Test
//let str = "1000000 2000 400 2938 292919"

let scanner:NSScanner = NSScanner.localizedScannerWithString(str as String) as! NSScanner
let skipChars = NSMutableCharacterSet(charactersInString: " ") // not sure if it contributes for speed
scanner.charactersToBeSkipped = skipChars
var count = 0
while true {
    var num:Int = 0
    let success = scanner.scanInteger(&num)
    if success {
        //print("Read \(num)")
        count = count + 1
    }
    else {
        break
    }
}
print("Completed: \(count) numbers found")


/////////////////////////////////////////////////////////////
// Benchmark Bash Script
//SECONDS=0
//cat input06.txt | ./HackerRanking
//duration=$SECONDS
//echo "$(($duration / 60)) minutes and $(($duration % 60)) seconds elapsed."
/////////////////////////////////////////////////////////////