Day 4

2024/day-4/solution-2.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+
+paste -s -d '' input.txt | 
+  perl -lne '
+    print "$1$4$2$3" 
+    while 
+      /(?<=(.).)(?<=(.).{138})A(?=.{138}(.))(?=.(.))/g
+  ' | 
+  grep -Eo '(SM|MS){2}' | 
+  wc -l