days 1, 2, 3

src/2024/day1/index.ts

@@ -0,0 +1,50 @@
+import { readFileSync } from 'fs';
+import { join } from 'path';
+import { DayOpts } from 'src/day';
+
+function day1(input: string): any {
+  const lines = input.split('\n');
+  let left: number[] = [];
+  let right: number[] = [];
+
+  for (const line of lines) {
+    const [ l, r ] = line.split(/ +/).map(Number);
+    left.push(l);
+    right.push(r);
+  }
+
+  left.sort((a, b) => a - b);
+  right.sort((a, b) => a - b);
+
+  let sum = 0;
+  for (let i = 0; i < left.length; i++) {
+    sum += Math.abs(left[i] - right[i]);
+  }
+
+  return sum;
+}
+
+export function day(input: string): any {
+  const lines = input.split('\n');
+  let left: number[] = [];
+  let right = new Map<number, number>();
+
+  for (const line of lines) {
+    const [ l, r ] = line.split(/ +/).map(Number);
+    left.push(l);
+    right.set(r, (right.get(r) ?? 0) + 1);
+  }
+
+  let sum = 0;
+  for (const l of left) {
+    sum += l * (right.get(l) ?? 0);
+  }
+
+  return sum;
+}
+
+export const opts: DayOpts = {
+  input: readFileSync(join(__dirname, './input.txt')).toString(),
+  sampleInput: readFileSync(join(__dirname, './sample.txt')).toString(),
+  sampleAnswer: 11,
+};

src/2024/day1/sample.txt

@@ -0,0 +1,6 @@
+3   4
+4   3
+2   5
+1   3
+3   9
+3   3

src/2024/day2/index.ts

@@ -0,0 +1,67 @@
+import { readFileSync } from 'fs';
+import { join } from 'path';
+import { DayOpts } from 'src/day';
+
+const isLevelSafe = (level: number[]) => {
+  let pos = level[0] > level[1];
+  for (let i = 0; i < level.length; i++) {
+    const curr = level[i];
+    const next = level[i + 1];
+    const diff = pos ? (curr - next) : (next - curr);
+    if (diff < 1 || diff > 3) {
+      return false;
+    }
+  }
+
+  return true;
+};
+
+function day1(input: string): any {
+  const lines = input.split('\n');
+  let sum = 0;
+  const levels: number[][] = [];
+
+  for (const line of lines) {
+    levels.push(line.split(' ').map(Number));
+  }
+
+  for (const level of levels) {
+    if (isLevelSafe(level)) {
+      sum++;
+    }
+  }
+
+  return sum;
+}
+
+export function day(input: string): any {
+  const lines = input.split('\n');
+  let sum = 0;
+  const levels: number[][] = [];
+
+  for (const line of lines) {
+    levels.push(line.split(' ').map(Number));
+  }
+
+  for (const level of levels) {
+    let safe = isLevelSafe(level);
+
+    for (let i = 0; i <= level.length; i++) {
+      const l2 = [ ...level ];
+      l2.splice(i, 1);
+      safe ||= isLevelSafe(l2);
+    }
+
+    if (safe) {
+      sum++;
+    }
+  }
+
+  return sum;
+}
+
+export const opts: DayOpts = {
+  input: readFileSync(join(__dirname, './input.txt')).toString(),
+  sampleInput: readFileSync(join(__dirname, './sample.txt')).toString(),
+  sampleAnswer: 4,
+};

src/2024/day2/sample.txt

@@ -0,0 +1,6 @@
+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

src/2024/day3/index.ts

@@ -0,0 +1,34 @@
+import { readFileSync } from 'fs';
+import { join } from 'path';
+import { DayOpts } from 'src/day';
+
+export function day(input: string): any {
+  const lines = input.split('\n');
+  let sum = 0;
+
+  let doing = true;
+
+  for (let line of lines) {
+    const matches = line.match(/(mul\((\d+),(\d+)\))|(do\(\))|(don't\(\))/g);
+    for (const match of matches ?? []) {
+      if (match === 'do()') {
+        doing = true;
+      } else if (match === 'don\'t()') {
+        doing = false;
+      }
+
+      if (match.startsWith('mul') && doing) {
+        const [ _, a, b ] = match.match(/mul\((\d+),(\d+)\)/);
+        sum += Number(a) * Number(b);
+      }
+    }
+  }
+
+  return sum;
+}
+
+export const opts: DayOpts = {
+  input: readFileSync(join(__dirname, './input.txt')).toString(),
+  sampleInput: readFileSync(join(__dirname, './sample.txt')).toString(),
+  sampleAnswer: 48,
+};

src/2024/day3/sample.txt

@@ -0,0 +1 @@
+xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))