Solve 2024-02

2024/02/2024-02.run.xml

@@ -0,0 +1,7 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="2024-02" type="BunRunConfiguration">
+    <option name="program" value="2024/02/run.ts" />
+    <option name="workingDirectory" value="$PROJECT_DIR$" />
+    <method v="2" />
+  </configuration>
+</component>

2024/02/index.test.ts

@@ -0,0 +1,17 @@
+import { describe, expect, it } from 'bun:test';
+import { solveFirst, solveSecond } from './index.ts';
+
+describe('2024-02', () => {
+  const testInput = `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`;
+  it('first', () => {
+    expect(solveFirst(testInput)).toBe(2);
+  });
+  it('second', () => {
+    expect(solveSecond(testInput)).toBe(4);
+  });
+});

2024/02/index.ts

@@ -0,0 +1,43 @@
+const isSafe = (numbers: number[]) => {
+  const increasing = numbers[1] - numbers[0];
+
+  for (let i = 1; i < numbers.length; i++) {
+    const signedDiff = numbers[i] - numbers[i - 1];
+    if (signedDiff < 0 !== increasing < 0) {
+      return false;
+    }
+
+    const diff = Math.abs(signedDiff);
+    if (diff < 1 || diff > 3) {
+      return false;
+    }
+  }
+
+  return true;
+};
+
+export function solveFirst(input: string): number {
+  const lines = input.split('\n').map((line) => line.split(' ').map(Number));
+
+  return lines.filter(isSafe).length;
+}
+
+export function solveSecond(input: string): number {
+  const lines = input.split('\n').map((line) => line.split(' ').map(Number));
+
+  const safe = lines.filter((numbers) => {
+    if (isSafe(numbers)) {
+      return true;
+    }
+
+    for (let i = 0; i < numbers.length; i++) {
+      if (isSafe(numbers.toSpliced(i, 1))) {
+        return true;
+      }
+    }
+
+    return false;
+  });
+
+  return safe.length;
+}

2024/02/run.ts

@@ -0,0 +1,12 @@
+import { join } from 'path';
+import { solveFirst, solveSecond } from './index.ts';
+
+const input = await Bun.file(join(__dirname, 'input.txt')).text();
+
+const firstAnswer = solveFirst(input);
+
+console.log(firstAnswer);
+
+const secondAnswer = solveSecond(input);
+
+console.log(secondAnswer);