Day 10

10/02.sh

@@ -0,0 +1,62 @@
+#!/bin/bash
+
+scores=()
+while read line; do
+  chars=( $(sed 's/\(.\)/\1 /g' <<< $line) )
+  opened_chars=()
+  broken=0
+  for char in ${chars[@]}; do
+    case $char in
+      '('|'['|'{'|'<')
+        opened_chars+=( $char );;
+      ')')
+	if [ ${opened_chars[-1]} = '(' ]; then
+	  unset 'opened_chars[-1]'
+	else
+	  broken=1
+	  break
+	fi;;
+      ']')
+	if [ ${opened_chars[-1]} = '[' ]; then
+	  unset 'opened_chars[-1]'
+	else
+	  broken=1
+	  break
+	fi;;
+      '}')
+	if [ ${opened_chars[-1]} = '{' ]; then
+	  unset 'opened_chars[-1]'
+	else
+	  broken=1
+	  break
+	fi;;
+      '>')
+	if [ ${opened_chars[-1]} = '<' ]; then
+	  unset 'opened_chars[-1]'
+	else
+	  broken=1
+	  break
+	fi;;
+    esac
+  done
+  if [ $broken -eq 0 ]; then
+    score=0
+    n_opened_chars=${#opened_chars[@]}
+    for i in $(seq $((n_opened_chars-1)) -1 0); do
+      case ${opened_chars[$i]} in
+        '(')
+          score=$((score*5+1));;
+        '[')
+          score=$((score*5+2));;
+        '{')
+          score=$((score*5+3));;
+        '<')
+          score=$((score*5+4));;
+      esac
+    done
+    scores+=( $score )
+  fi
+done
+scores=( $(printf '%s\n' "${scores[@]}" | sort -nr) )
+n_scores=${#scores[@]}
+echo ${scores[$((n_scores/2))]}