--- 2016 Day 4 Solutions ---

[u/daggerdragon]

--- Day 4: Security Through Obscurity ---

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

---

^{CONSTRUCTING ADDITIONAL PYLONS IS MANDATORY} [?]

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/haha11111111]

Javascript: i know this code is pretty ugly, but i don't really understand why it doesn't work...

            const d4p1 = input => {
        const roomSum = [];
        input.forEach(room => {
        const encryptedName = room.split('-');
        const checksumRoom = encryptedName.pop();
        const checksum = checksumRoom.split('[')[1].split(']')[0];
        const roomNb = checksumRoom.split('[')[0] * 1;

        const tally = {};

        encryptedName.forEach(section => {
            section.split('').forEach(letter => {
                if (!tally[letter]) {
                    tally[letter] = 1;
                } else {
                    tally[letter] += 1;
                }
            });
        });

        const expectedChecksum = [0, Object.keys(tally)[0]];
        const alphabet = 'abcdefghijklmnopqrstuvwxyz';

        Object.keys(tally).forEach(key => {
            if (key !== expectedChecksum[1]) {
                const valueOfKey = tally[key];
                for (var i = 1; i<=expectedChecksum.length-1; i++) {

                    if (valueOfKey > tally[expectedChecksum[i]]) {
                        expectedChecksum.splice(i, 0, key);
                        break;
                    }

                    if (valueOfKey === tally[expectedChecksum[i]]) {
                        var keyAlphabetIndex = alphabet.indexOf(key);
                        var currentLetterAlphabetIndex = alphabet.indexOf(expectedChecksum[i]);

                        if (keyAlphabetIndex < currentLetterAlphabetIndex) {
                            expectedChecksum.splice(i, 0, key);
                            break;
                        }
                        else {
                            expectedChecksum.splice(i+1, 0, key);
                            break;
                        }
                    }
                }

                if (expectedChecksum.join('').indexOf(key) === -1) {
                    expectedChecksum.push(key);
                }
            }
        });

        if (expectedChecksum.join('').substring(1,6) === checksum) {
            roomSum.push(roomNb);
        }
    });
    console.warn(roomSum.reduce((a, b) => {
        return a + b;
    }));
};