snail

snail.swift

//convert to ruby

//: Playground - noun: a place where people can play

import UIKit

let result = [1, 2, 3, 4, 5, 10, 15, 20, 25, 24, 23, 22, 21, 16, 11, 6, 7, 8, 9, 14, 19, 18, 17, 12, 13]

enum Direction {
    case Right, Left, Up, Down
    func nextDirection() -> Direction {
        switch self {
        case .Right:
            return .Down
        case .Down:
            return .Left
        case .Up:
            return .Right
        case .Left:
            return .Up
        }
    }
}

//test([[1, 2, 3, 4, 5], [6, 7, 8, 9, 10], [11, 12, 13, 14, 15], [16, 17, 18, 19, 20], [21, 22, 23, 24, 25]], [1, 2, 3, 4, 5, 10, 15, 20, 25, 24, 23, 22, 21, 16, 11, 6, 7, 8, 9, 14, 19, 18, 17, 12, 13]) 

func snail(array: [[Int]]) -> [Int] {
    var ary: [Int] = []
    var currentDirection = Direction.Right
    let aryLength = array.count * array.count
    var counter = 0
    var row = 0
    var col = 0
    let width = array.count
    let height = array.count
    var widthOffset = 0
    var heightOffset = 0
    var numTurns = 0
    
    while counter < aryLength {
        switch currentDirection {
        case .Right:
            ary.insert(array[row][col], atIndex: counter)
            col++
            widthOffset = (numTurns > 3) ? 1 : 0
            if col == width - widthOffset {
                currentDirection = currentDirection.nextDirection()
                numTurns++
                //when we change the direction increment row!
                row++
                col--
            }
        case .Down:
            ary.insert(array[row][col], atIndex: counter)
            row++
            heightOffset = (numTurns > 3) ? 1 : 0
            if row == height - heightOffset {
                currentDirection = currentDirection.nextDirection()
                numTurns++
                col--
                row--
            }
            break
        case .Left:
            ary.insert(array[row][col], atIndex: counter)
            col--
            if col == -1 + widthOffset {
                currentDirection = currentDirection.nextDirection()
                numTurns++
                col++
                row--
            }
            break
        case .Up:
            ary.insert(array[row][col], atIndex: counter)
            row--
            if row == 0 + widthOffset {
                currentDirection = currentDirection.nextDirection()
                numTurns++
                row++
                col++
            }
            break
        }
        counter++
    }
    
    return ary
}

snail([[1, 2, 3, 4, 5], [6, 7, 8, 9, 10], [11, 12, 13, 14, 15], [16, 17, 18, 19, 20], [21, 22, 23, 24, 25]]) == result