import Cocoa

let levels: [[Int]] = [
    [04, 62, 98, 27, 23, 09, 70, 98, 73, 93, 38, 53, 60, 04, 23],
      [63, 66, 04, 68, 89, 53, 67, 30, 73, 16, 69, 87, 40, 31],
        [91, 71, 52, 38, 17, 14, 91, 43, 58, 50, 27, 29, 48],
          [70, 11, 33, 28, 77, 73, 17, 78, 39, 68, 17, 57],
            [53, 71, 44, 65, 25, 43, 91, 52, 97, 51, 14],
              [41, 48, 72, 33, 47, 32, 37, 16, 94, 29],
                [41, 41, 26, 56, 83, 40, 80, 70, 33],
                  [99, 65, 04, 28, 06, 16, 70, 92],
                    [88, 02, 77, 73, 07, 63, 67],
                      [19, 01, 23, 75, 03, 34],
                        [20, 04, 82, 47, 65],
                          [18, 35, 87, 10],
                            [17, 47, 82],
                              [95, 64],
                                [75]]

func p18() -> Int {
    var lastLevelScores = levels[0]
    for level in levels[1..<levels.count] {
        var levelScores: [Int] = []
        for i in 0..<level.count{
            let betterPathScore = max(lastLevelScores[i], lastLevelScores[i + 1])
            levelScores.append(level[i] + betterPathScore)
        }
        lastLevelScores = levelScores
    }

    return lastLevelScores[0]
}
p18()
