feat(2024-02): Add day 2

AdventOfCode JS/2024/Day02.test.js

@@ -0,0 +1,149 @@
+const fs = require("fs");
+const path = require("path");
+
+describe("2024 Day 02", () => {
+  let realData;
+
+  beforeAll(() => {
+    const filePath = path.resolve(__dirname, "./Data/Day02.dat");
+    realData = fs.readFileSync(filePath, "utf-8").split("\n");
+  });
+
+  function areNumbersAllIncreasingOrDecreasing(numbers) {
+    if (numbers.length <= 1) {
+      // If there's only one number, it's either increasing or decreasing
+      return true;
+    }
+
+    let isIncreasing = true;
+    let isDecreasing = true;
+
+    for (let i = 1; i < numbers.length; i++) {
+      if (numbers[i] > numbers[i - 1]) {
+        isDecreasing = false;
+      } else if (numbers[i] < numbers[i - 1]) {
+        isIncreasing = false;
+      }
+
+      if (!isIncreasing && !isDecreasing) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+  function areAdjacentNumbersWithinRange(numbers) {
+    for (let i = 1; i < numbers.length; i++) {
+      const diff = Math.abs(numbers[i] - numbers[i - 1]);
+      if (diff < 1 || diff > 3) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  function isReportSafe(report) {
+    const numbers = report.split(" ").map((x) => parseInt(x, 10));
+
+    if (!areNumbersAllIncreasingOrDecreasing(numbers)) {
+      return false;
+    }
+
+    if (!areAdjacentNumbersWithinRange(numbers)) {
+      return false;
+    }
+
+    return true;
+  }
+
+  function isReportSafeAllowRemovingOneNumber(report) {
+    const numbers = report.split(" ").map((x) => parseInt(x, 10));
+
+    function isSafe(numbers) {
+      return (
+        areNumbersAllIncreasingOrDecreasing(numbers) &&
+        areAdjacentNumbersWithinRange(numbers)
+      );
+    }
+
+    if (isSafe(numbers)) {
+      return true;
+    }
+
+    // Try removing each number and check if the resulting array is safe
+    for (let i = 0; i < numbers.length; i++) {
+      const modifiedNumbers = [...numbers.slice(0, i), ...numbers.slice(i + 1)];
+      if (isSafe(modifiedNumbers)) {
+        return true;
+      }
+    }
+
+    // If no single removal makes the report safe, return false
+    return false;
+  }
+
+  function part1(input) {
+    // In the input, each line is a report
+    const reports = input.split("\n");
+    // Each report is a string of numbers separated by spaces
+
+    let amountOfSafeReports = 0;
+
+    reports.forEach((report) => {
+      if (isReportSafe(report)) {
+        amountOfSafeReports += 1;
+      }
+    });
+
+    return amountOfSafeReports;
+  }
+
+  function part2(input) {
+    // In the input, each line is a report
+    const reports = input.split("\n");
+    // Each report is a string of numbers separated by spaces
+
+    let amountOfSafeReports = 0;
+
+    reports.forEach((report) => {
+      if (isReportSafeAllowRemovingOneNumber(report)) {
+        amountOfSafeReports += 1;
+      }
+    });
+
+    return amountOfSafeReports;
+  }
+
+  test.each([
+    [
+      `7 6 4 2 1
+  1 2 7 8 9
+  9 7 6 2 1
+  1 3 2 4 5
+  8 6 4 4 1
+  1 3 6 7 9`,
+      2,
+    ],
+    [null, 585], // The actual answer
+  ])("Part 1: %s -> %i", (input, expected) => {
+    const result = part1(input ? input : realData.join("\n"));
+    expect(result).toBe(expected);
+  });
+
+  test.each([
+    [
+      `7 6 4 2 1
+1 2 7 8 9
+9 7 6 2 1
+1 3 2 4 5
+8 6 4 4 1
+1 3 6 7 9`,
+      4,
+    ],
+    [null, 626], // The actual answer
+  ])("Part 2: %s -> %i", (input, expected) => {
+    const result = part2(input ? input : realData.join("\n"));
+    expect(result).toBe(expected);
+  });
+});