From 1ff50f072e98263f9bb489ef98a59f7052ca6e2d Mon Sep 17 00:00:00 2001
From: Max Nuding <max.nuding@icloud.com>
Date: Thu, 9 Dec 2021 07:48:45 +0100
Subject: [PATCH] RafaSwitched to sequence

---
 Sources/09/09.swift   | 33 ++++++++++++++++++++++++---------
 Sources/09/main.swift |  4 ++--
 2 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/Sources/09/09.swift b/Sources/09/09.swift
index fb01a62..89662d5 100644
--- a/Sources/09/09.swift
+++ b/Sources/09/09.swift
@@ -32,11 +32,13 @@ struct Coord {
     func getBelow() -> Coord { Coord(row: row + 1, col: col) }
 }
 
-struct Field {
+struct Field:Sequence, IteratorProtocol {
     let numbers: [[Int]]
     let numCols: Int
     let numRows: Int
     
+    var current: Coord? = Coord(row: 0, col: 0)
+    
     init(numbers: [[Int]]) {
         self.numbers = numbers
         numCols = numbers.first!.count
@@ -57,6 +59,26 @@ struct Field {
         ? value
         : nil
     }
+    
+    private func getNextCoord() -> Coord? {
+        guard let current = current else {
+            return nil
+        }
+        if current.col == numCols - 1 && current.row == numRows - 1 {
+            return nil
+        }
+        if current.col == numCols - 1 {
+            return Coord(row: current.row + 1, col: 0)
+        }
+        return Coord(row: current.row, col: current.col + 1)
+    }
+    
+    mutating func next() -> Coord? {
+        defer {
+            current = getNextCoord()
+        }
+        return current
+    }
 }
 
 struct Day09: Runnable {
@@ -69,14 +91,7 @@ struct Day09: Runnable {
             .components(separatedBy: .newlines)
             .map { line in line.map { $0.wholeNumberValue! } }
         let field = Field(numbers: entries)
-        var sum = 0
-        for row in 0..<field.numRows {
-            for col in 0..<field.numCols {
-                if let lpv = field.lowPointValueAt(coord: Coord(row: row, col: col)) {
-                    sum += lpv + 1
-                }
-            }
-        }
+        let sum = field.compactMap { field.lowPointValueAt(coord: $0) }.reduce(0, { $0 + $1 + 1 })
         print(sum)
     }
 }
diff --git a/Sources/09/main.swift b/Sources/09/main.swift
index 40cb1e4..ec52da1 100644
--- a/Sources/09/main.swift
+++ b/Sources/09/main.swift
@@ -8,5 +8,5 @@
 import Foundation
 import Runner
 
-//Runner(target: Day09.self, day: "09", isTest: true).run()
-Runner(target: Day09.self, day: "09", isTest: false).run()
+Runner(target: Day09.self, day: "09", isTest: true).run()
+//Runner(target: Day09.self, day: "09", isTest: false).run()