SwiftSpiral

SwiftSpiral

import UIKit

enum Dimension {
    case X, Y
}

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        
        var out = buildSpiral(12)
        for i in 0..<out.count {
            printLine(out[i])
        }
    }
    
    func printLine(line: [Bool]) {
        let asterisk = "*"
        let space = " "
        var output = ""
        for i in 0..<line.count {
            output += line[i] ? asterisk : space
        }
        
        println(output)
    }
    func buildSpiral(size: Int) -> [[Bool]] {
        var spiral: [[Bool]] = []
        
        for i in 0..<size {
            var row: [Bool] = []
            for i in 0..<size {
                row += [false]
            }
            spiral += [row]
        }
        
        var position: (x: Int, y: Int) = (0,0)
        var maxDim = size - 1
        var activeDimension = Dimension.X
        var direction = 1
        var count = 0
        while maxDim > 0 {
            for i in 0...maxDim {
                spiral[position.y][position.x] = true
                
                if i != maxDim {
                    if activeDimension == Dimension.X {
                        position.x = position.x + direction
                    }
                    else {
                        position.y = position.y + direction
                    }
                }
            }
            
            if activeDimension == Dimension.X {
                activeDimension = Dimension.Y
            }
            else {
                activeDimension = Dimension.X
            }
            if ++count % 2 == 0 {
                direction *= -1
                maxDim-=2
            }
        }
        return spiral
    }

}