From 6f7fc2d1a878e0f31aebe9ab100fb0a4da346f6a Mon Sep 17 00:00:00 2001
From: Sven Weidauer <sven@5sw.de>
Date: Sat, 7 Dec 2024 13:10:21 +0100
Subject: [PATCH] Use substring iterator directly

---
 2024/src/main/kotlin/Grid.kt | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/2024/src/main/kotlin/Grid.kt b/2024/src/main/kotlin/Grid.kt
index 44bbda0..cfad170 100644
--- a/2024/src/main/kotlin/Grid.kt
+++ b/2024/src/main/kotlin/Grid.kt
@@ -13,23 +13,21 @@ class Grid(val rows: List<String>) {
     fun chars(x: Int, y: Int, dx: Int, dy: Int) = Line(x, y, dx, dy)
 
     inner class Line(val x: Int, val y: Int, val dx: Int, val dy: Int) : Sequence<Char> {
-        override fun iterator(): Iterator<Char> = iterator {
-            if (dx == 1 && dy == 0) {
-                yieldAll(rows[y].substring(startIndex = x).asSequence())
-            } else {
+        override fun iterator(): Iterator<Char> = if (dx == 1 && dy == 0) {
+            rows[y].substring(startIndex = x).iterator()
+        } else iterator {
+            var x = x
+            var y = y
 
-                var x = x
-                var y = y
-
-                while (x in 0..<width && y in 0..<height) {
-                    yield(get(x, y))
-                    x += dx
-                    y += dy
-                }
+            while (x in 0..<width && y in 0..<height) {
+                yield(get(x, y))
+                x += dx
+                y += dy
             }
         }
     }
 
+
     fun rows(): Sequence<Line> = sequence {
         for (y in 0..<height) {
             yield(chars(0, y, 1, 0))