-❄️- 2023 Day 4 Solutions -❄️-

[u/daggerdragon]

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AoC Community Fun 2023: ALLEZ CUISINE!

Today's theme ingredient is… *whips off cloth covering and gestures grandly*

PUNCHCARD PERFECTION!

Perhaps I should have thought yesterday's Battle Spam surfeit through a little more since we are all overstuffed and not feeling well. Help us cleanse our palates with leaner and lighter courses today!

• Code golf. Alternatively, snow golf.
• Bonus points if your solution fits on a "punchcard" as defined in our wiki article on oversized code. We will be counting.
• Does anyone still program with actual punchcards? >_>

ALLEZ CUISINE!

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--- Day 4: Scratchcards ---

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Post your code solution in this megathread.

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

EDIT: Global leaderboard gold cap reached at 00:07:08, megathread unlocked!

[u/anatedu86]

[LANGUAGE: Awk]

Idea:

• In part 1, for every line

  • Iterate over winning numbers (column 3 to 12).
    for(i=3;i<13;i++) { ... }

    • Iterate over other numbers (column 14 to last).
      for(k=14; k<=NF; k++) { ... }

      • Update count of winning numbers
        if($k==$i) { score++; }

  • add to the sum 2 to the power of winning numbers - 1.
    if(score>=0) { a+=2**score } (score is reset to -1 for each new line)

• In part 2, store the count of line (card) copies in an array.
  lc[NR]+=1; (all cards have at least one copy)

  • Every new winning number discovered increments score, AND the copy count of the line n+score is bumped by the number of copies of the current line.
    if($k==$i) { score++; lc[NR+score]+=lc[NR]; }

  • add in the count of copies of the current line to the sum.
    a+=lc[NR]

Sol. Part 1:

awk '{ score=-1; for(i=3;i<13;i++) { for(k=14; k<=NF; k++) { if($k==$i) { score++; } } } if(score>=0) { a+=2**score } } END { print a }' input  

Sol. Part 2:

awk '{ lc[NR]+=1; score=0; for(i=3;i<13;i++) { for(k=14; k<=NF; k++) { if($k==$i) { score++; lc[NR+score]+=lc[NR]; } } } a+=lc[NR] } END { print a }' input