Advent of Code Day 6

part1.js

const { readFile } = require("fs/promises");
async function readRawInput(path) {
  const content = await readFile(path, { encoding: "utf-8" });
  return content;
}

/**
 * @param {string} fourCharacters ex "abcd"
 * @returns true if all unique. false if there's a repeating character.
 */
function allUnique(fourCharacters) {
    for (let i = 0; i < 4; i++) {
        const char = fourCharacters[i];
        for (let j = i + 1; j < 4; j++) {
            if (char === fourCharacters[j]) {
                return false;
            }
        }
    }
    return true;
}

async function main() {
    const raw = await readRawInput("./input.txt");
    console.log("length", raw.length);
    for (let i = 0; i < raw.length - 4; i++) {
        const fourChars = raw.substring(i, i + 4);
        if (allUnique(fourChars)) {
            console.log(i + 4);
            return;
        }
    }
}
main();

part2.js

const { readFile } = require("fs/promises");
async function readRawInput(path) {
  const content = await readFile(path, { encoding: "utf-8" });
  return content;
}

/**
 * @param {string} fourteenCharacters
 * @returns true if all unique. false if there's a repeating character.
 */
function allUnique(fourteenCharacters) {
    for (let i = 0; i < 14; i++) {
        const char = fourteenCharacters[i];
        for (let j = i + 1; j < 14; j++) {
            if (char === fourteenCharacters[j]) {
                return false;
            }
        }
    }
    return true;
}

async function main() {
    const raw = await readRawInput("./input.txt");
    console.log("length", raw.length);
    for (let i = 0; i < raw.length - 14; i++) {
        const fourChars = raw.substring(i, i + 14);
        if (allUnique(fourChars)) {
            console.log(i + 14);
            return;
        }
    }
}
main();