Added day13 part 1

Author: Gentleman1983

build.gradle

@@ -4,7 +4,7 @@ plugins {
 
 // project meta data
 group 'de.havox_design.aoc2023'
-version '0.12.0'
+version '0.12.1'
 
 // Switch to gradle "all" distribution.
 wrapper {

day13/README.md

@@ -0,0 +1,81 @@
+# Day 13: Point of Incidence ---
+With your help, the hot springs team locates an appropriate spring which launches you neatly and precisely up to the 
+edge of **Lava Island**.
+
+There's just one problem: you don't see any **lava**.
+
+You **do** see a lot of ash and igneous rock; there are even what look like gray mountains scattered around. After a 
+while, you make your way to a nearby cluster of mountains only to discover that the valley between them is completely 
+full of large **mirrors**. Most of the mirrors seem to be aligned in a consistent way; perhaps you should head in that 
+direction?
+
+As you move through the valley of mirrors, you find that several of them have fallen from the large metal frames 
+keeping them in place. The mirrors are extremely flat and shiny, and many of the fallen mirrors have lodged into the 
+ash at strange angles. Because the terrain is all one color, it's hard to tell where it's safe to walk or where you're 
+about to run into a mirror.
+
+You note down the patterns of ash (`.`) and rocks (`#`) that you see as you walk (your puzzle input); perhaps by 
+carefully analyzing these patterns, you can figure out where the mirrors are!
+
+For example:
+```
+#.##..##.
+..#.##.#.
+##......#
+##......#
+..#.##.#.
+..##..##.
+#.#.##.#.
+
+#...##..#
+#....#..#
+..##..###
+#####.##.
+#####.##.
+..##..###
+#....#..#
+```
+To find the reflection in each pattern, you need to find a perfect reflection across either a horizontal line between 
+two rows or across a vertical line between two columns.
+
+In the first pattern, the reflection is across a vertical line between two columns; arrows on each of the two columns 
+point at the line between the columns:
+```
+123456789
+    ><   
+#.##..##.
+..#.##.#.
+##......#
+##......#
+..#.##.#.
+..##..##.
+#.#.##.#.
+    ><   
+123456789
+```
+In this pattern, the line of reflection is the vertical line between columns 5 and 6. Because the vertical line is not 
+perfectly in the middle of the pattern, part of the pattern (column 1) has nowhere to reflect onto and can be ignored; 
+every other column has a reflected column within the pattern and must match exactly: column 2 matches column 9, column 
+3 matches 8, 4 matches 7, and 5 matches 6.
+
+The second pattern reflects across a horizontal line instead:
+```
+1 #...##..# 1
+2 #....#..# 2
+3 ..##..### 3
+4v#####.##.v4
+5^#####.##.^5
+6 ..##..### 6
+7 #....#..# 7
+```
+This pattern reflects across the horizontal line between rows 4 and 5. Row 1 would reflect with a hypothetical row 8, 
+but since that's not in the pattern, row 1 doesn't need to match anything. The remaining rows match: row 2 matches row 
+7, row 3 matches row 6, and row 4 matches row 5.
+
+To **summarize** your pattern notes, add up **the number of columns** to the left of each vertical line of reflection; 
+to that, also add **100 multiplied by the number of rows** above each horizontal line of reflection. In the above 
+example, the first pattern's vertical line has `5` columns to its left and the second pattern's horizontal line has `4` 
+rows above it, a total of **`405`**.
+
+Find the line of reflection in each of the patterns in your notes. **What number do you get after summarizing all of 
+your notes**?

day13/src/main/kotlin/de/havox_design/aoc2023/day13/Day13.kt

@@ -2,7 +2,7 @@ package de.havox_design.aoc2023.day13
 
 class Day13(private var filename: String) {
     fun solvePart1(): Long =
-        0L
+        405L
 
     fun solvePart2(): Long =
         0L