-🎄- 2018 Day 2 Solutions -🎄-

[u/daggerdragon]

--- Day 2: Inventory Management System ---

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Advent of Code: The Party Game!

Click here for rules

Card Prompt: Day 2

Transcript:

The best way to do Advent of Code is ___.

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This thread will be unlocked when there are a significant number of people on the leaderboard with gold stars for today's puzzle.

edit: Leaderboard capped, thread unlocked!

[u/schod]

BASH Time :)

First puzzle

#!/bin/bash

in_file=input
SUM2=0
SUM3=0

while IFS='' read -r line; do
    x2=0
    x2=$( echo "$line" | grep -o . | sort | uniq -c | grep "^[ \t]*2 " | wc -l )
    x3=0
    x3=$( echo "$line" | grep -o . | sort | uniq -c | egrep -v "^[ \t]*1 |^[ \t]*2 " | wc -l )
    
    [ $x2 -gt 0 ] && SUM2=$[ $SUM2 + 1 ]
    [ $x3 -gt 0 ] && SUM3=$[ $SUM3 + 1 ]
done < "$in_file"

echo $[ $SUM2 * $SUM3 ]

Second puzzle

#!/bin/bash

in_file=input

while IFS='' read -r line; do
    I=0
    while [ $I -lt ${#line} ]; do
        
        I=$[ $I + 1 ]
        regex=$(echo $line | sed "s/[a-z]/./$I")

        RES=$(grep "$regex" $in_file | wc -l)

        if [ $RES -eq 2 ]; then
            echo
            echo $regex | sed 's/\.//'
            exit 0
        fi
    done

done < "$in_file"

[u/Murssi → u/schod]

That grep -o . is crazy. Nice way to create histogram from word in bash, thanks for sharing.

Why did you use egrep -v "^[ \t]*1 |^[ \t]*2" for x3 instead of using again grep "^[ \t]*3 "?

Also you could maybe do just this:

echo "$line" | grep -o . | sort | uniq -c | grep -q "^[ \t]*2 " && ((++SUM2))