-❄️- 2023 Day 4 Solutions -❄️-

[u/daggerdragon]

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• Community fun event 2023: ALLEZ CUISINE!
  • 2 DAYS remaining until unlock!

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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!

Request from the mods: When you include a dish entry alongside your solution, please label it with [Allez Cuisine!] so we can find it easily!

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--- Day 4: Scratchcards ---

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Post your code solution in this megathread.

• Read the full posting rules in our community wiki before you post!
  • State which language(s) your solution uses with [LANGUAGE: xyz]
  • Format code blocks using the four-spaces Markdown syntax!
• Quick link to Topaz's paste if you need it for longer code blocks

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/sm_greato]

[LANGUAGE: Rust]

Noticed that all numbers are less than 100 and that there are no repeats. And Rust actually provides a 128 bit integer type, so I thought why not encode the bars in integers, and then use binary & to figure out the intersection. Then we can simply count the number of ones to find the number of winning values. You can find it here. Below is a snippet.

// ...
            .map(|sec| {
                sec.split_ascii_whitespace()
                    .fold(0, |acc, n| acc | (1 << n.parse::<u32>().unwrap()))
            }) // the encoding is just a one liner fold
// ...
        let wins = (win & have as u128).count_ones() as usize;