Solution day 13

Author: damyvv

README.md

@@ -14,7 +14,7 @@
 |[10](https://adventofcode.com/2022/day/10)|Cathode-Ray Tube|[view](solutions/day10.rb)|⭐ ⭐|
 |[11](https://adventofcode.com/2022/day/11)|Monkey in the Middle|[view](solutions/day11.rb)|⭐ ⭐|
 |[12](https://adventofcode.com/2022/day/12)|Hill Climbing Algorithm|[view](solutions/day12.rb)|⭐ ⭐|
-|[13](https://adventofcode.com/2022/day/13)||[view](solutions/day13.rb)||
+|[13](https://adventofcode.com/2022/day/13)|Distress Signal|[view](solutions/day13.rb)|⭐ ⭐|
 |[14](https://adventofcode.com/2022/day/14)||[view](solutions/day14.rb)||
 |[15](https://adventofcode.com/2022/day/15)||[view](solutions/day15.rb)||
 |[16](https://adventofcode.com/2022/day/16)||[view](solutions/day16.rb)||

solutions/day13.rb

@@ -0,0 +1,20 @@
+packets = File.read("day13_input.txt").split("\n\n").map {|l| l.split.map {|a| eval a.strip } }
+
+def cmp_arr(a,b)
+ if !a.kind_of?(Array) && !b.kind_of?(Array)
+ a <=> b
+ else
+ a = [a] unless a.kind_of?(Array)
+ b = [b] unless b.kind_of?(Array)
+ a.each_with_index do |ai,i|
+ break if b[i].nil?
+ cmp = cmp_arr(ai,b[i])
+ return cmp unless cmp == 0
+ end
+ a.length - b.length
+ end
+end
+
+p packets.map.with_index {|arr,i| arr.sort {|a,b| cmp_arr(a,b) } == arr ? i+1 : 0 }.sum
+sorted = (packets + [[[[2]], [[6]]]]).flatten(1).sort {|a,b| cmp_arr(a,b) }
+p (sorted.find_index([[2]])+1) * (sorted.find_index([[6]])+1)