advent-of-code/2024/day-5/solution-1.sh

#!/usr/bin/env bash

while read -r LINE
do
  GREP_EXPR=$( printf "%s"  "$LINE" | tr ',' '|' )
  PASS_RULES=0
  # Loop through rules and find a breaking rule
  while read -r RULE
  do
    GREPC=$( printf "%s" "$LINE" | grep -c "$RULE" ) 
    if [[ $GREPC -ne 1 ]]
    then
      #printf "%s rule violated for %s \n" "$RULE" "$LINE"
      PASS_RULES=1
      break
    fi
  # Filter rules that only has included pages
  done <<< "$( < input-rules grep -E "($GREP_EXPR)\\|($GREP_EXPR)" | sed 's/|/,.*/')" 
  # All rules have passed
  [[ $PASS_RULES -eq 0 ]] && printf "%s\n" "$LINE"
done < input-updates |
  tr ',' ' ' |
  awk '
  BEGIN{ total = 0 } 
  {
    if (NF % 2 == 1) {
      idx = int( NF / 2 ) + 1
    } else {
      idx = NF / 2
    }
    total += $idx
  } 
  END{ print total }'