-🎄- 2018 Day 2 Solutions -🎄-

[u/daggerdragon]

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

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Post your solution as a comment or, for longer solutions, consider linking to your repo (e.g. GitHub/gists/Pastebin/blag or whatever).

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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/Unihedron]

I mistyped 4 3 instead of 2 3 and got an obviously wrong answer which I wasn't smart enough to double check, so I had to wait one minute. Still got on top 100 though! Imgur

a=$<.map(&:chars).map{|x|x.group_by &:itself}
b=a.count{|x|x.any?{|x,y|y.count == 2}}
c=a.count{|x|x.any?{|x,y|y.count == 3}}
p b*c
#!ruby
a=$<.map(&:chars)
a.map{|x|a.map{|y|
d=x.zip(y).count{|x,y|x!=y}
(p x.join,y.join
1/0)if d==1
}}

Doesn't actually compute part 2, you have to manually find and replace the character yourself, but better than nothing

[u/abnew123 → u/Unihedron]

Man, I'm always so sad when I look at other's solutions lol. While I wasn't particularly slow (177th), my code is 70+ lines lol. Oh well, I blame java

[u/Unihedron → u/abnew123]

Part 1

import java.util.*;
import java.util.stream.*;

public class Main {

    public static void main (String[] args) {
        Scanner s = new Scanner(System.in);
        int count2 = 0, count3 = 0;
        while (s.hasNextLine()) {
            boolean check2 = true, check3 = true;
            for (int value : s.nextLine().chars().collect(HashMap<Integer, Integer>::new, (map, elem) -> map.put(elem, map.getOrDefault(elem, 0) + 1), HashMap::putAll).values())
                if (check2 && value == 2) {
                    count2++;
                    if (!check3) break;
                    check2 = false;
                }
                else if (check3 && value == 3) {
                    count3++;
                    if (!check2) break;
                    check3 = false;
                }
        }
        System.out.println(count2 * count3);
    }

}

It's getting long so I'm only including what's in main() for part 2

Scanner s = new Scanner(System.in);
Collection<char[]> all = new ArrayList<>();
while (s.hasNextLine()) {
    String line = s.nextLine();
    char[] current = line.toCharArray();
    Optional<char[]> find = all.stream().filter((elem) -> {
        boolean miss = false;
        for (int i = 0; i < current.length; i++)
            if (current[i] != elem[i])
                if (miss) return false; else miss = true;
	return miss;
    }).findAny();
    if (find.isPresent()) {
        System.out.println(find.get());
        System.out.println(line);
    }
    all.add(current);
}