feat: 2024 Day 19

Author: mfulton26

2024/day/19/part/1/solve.test.ts

@@ -0,0 +1,19 @@
+import solve from "./solve.ts";
+
+import { assertEquals } from "@std/assert";
+
+Deno.test("example", () => {
+  const input = `\
+r, wr, b, g, bwu, rb, gb, br
+
+brwrr
+bggr
+gbbr
+rrbgbr
+ubwu
+bwurrg
+brgr
+bbrgwb`;
+
+  assertEquals(solve(input), 6);
+});

2024/day/19/part/1/solve.ts

@@ -0,0 +1,9 @@
+export default function solve(input: string) {
+  const [top, bottom] = input.split("\n\n");
+  const patterns = top.split(", ");
+  const designs = bottom.split("\n");
+  let possibleCount = 0;
+  const tester = new RegExp(`^(?:${patterns.join("|")})+$`);
+  for (const design of designs) if (tester.test(design)) possibleCount++;
+  return possibleCount;
+}

2024/day/19/part/2/solve.test.ts

@@ -0,0 +1,19 @@
+import solve from "./solve.ts";
+
+import { assertEquals } from "@std/assert";
+
+Deno.test("example", () => {
+  const input = `\
+r, wr, b, g, bwu, rb, gb, br
+
+brwrr
+bggr
+gbbr
+rrbgbr
+ubwu
+bwurrg
+brgr
+bbrgwb`;
+
+  assertEquals(solve(input), 16);
+});

2024/day/19/part/2/solve.ts

@@ -0,0 +1,20 @@
+export default function solve(input: string) {
+  const [top, bottom] = input.split("\n\n");
+  const patterns = top.split(", ");
+  const maxPatternLength = Math.max(...patterns.map(({ length }) => length));
+  const designs = bottom.split("\n");
+  let possibleCount = 0;
+  const isPossibleRegExp = new RegExp(`^(?:${patterns.join("|")})+$`);
+  for (const design of designs) {
+    if (!isPossibleRegExp.test(design)) continue;
+    const counts = Array.from({ length: design.length + 1 }, () => 0);
+    counts[0] = 1;
+    for (let j = 1; j <= design.length; j++) {
+      for (let i = Math.max(0, j - maxPatternLength); i < j; i++) {
+        if (patterns.includes(design.slice(i, j))) counts[j] += counts[i];
+      }
+    }
+    possibleCount += counts.at(-1)!;
+  }
+  return possibleCount;
+}