day 19

src/19/input.test.ts

@@ -0,0 +1,14 @@
+import { assertEquals } from "@std/assert";
+import { main } from "./main.ts";
+
+const target = "input";
+
+Deno.test(`correct possible design count for ${target}`, async () => {
+  const result = await main(target);
+  assertEquals(result.possibleDesigns, 353);
+});
+
+Deno.test(`correct possible design combos for ${target}`, async () => {
+  const result = await main(target);
+  assertEquals(result.possibleDesignCombos, 880877787214477);
+});

src/19/main.ts

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+// { possibleDesigns: 353, possibleDesignCombos: 880877787214477 }
+// Elapsed: 133ms
+
+function testDesign(towels: string[], design: string): number {
+  const designCounter = new Array(design.length + 1).fill(0);
+  designCounter[0] = 1;
+  for (let i = 0; i <= design.length; i++) {
+    if (designCounter[i]) {
+      for (const towel of towels) {
+        if (
+          i + towel.length <= design.length &&
+          towel === design.slice(i, i + towel.length)
+        ) {
+          designCounter[i + towel.length] += designCounter[i];
+        }
+      }
+    }
+  }
+
+  return designCounter[design.length];
+}
+
+export async function main(target = "input") {
+  const dirpath = new URL(".", import.meta.url).pathname;
+  const text = await Deno.readTextFile(`${dirpath}${target}.txt`);
+
+  const { patterns, designs } = text.split("\n").reduce((agg, line) => {
+    if (line.match(/^[wubrg]+$/)) {
+      agg.designs.push(line);
+      return agg;
+    }
+
+    const towelsMatch = line.match(/^[wubrg, ]+$/);
+    if (towelsMatch) {
+      agg.patterns = towelsMatch[0].split(", ");
+    }
+
+    return agg;
+  }, { patterns: [] as string[], designs: [] as string[] });
+
+  return designs.reduce((agg, design) => {
+    const combos = testDesign(patterns, design);
+    agg.possibleDesigns += combos > 0 ? 1 : 0;
+    agg.possibleDesignCombos += combos;
+    return agg;
+  }, { possibleDesigns: 0, possibleDesignCombos: 0 });
+}
+
+if (import.meta.main) {
+  const startTime = performance.now();
+  console.log(await main());
+  console.log(`Elapsed: ${Math.round(performance.now() - startTime)}ms`);
+}

src/19/sample.txt

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+r, wr, b, g, bwu, rb, gb, br
+
+brwrr
+bggr
+gbbr
+rrbgbr
+ubwu
+bwurrg
+brgr
+bbrgwb

src/19/test.ts

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+import { assertEquals } from "@std/assert";
+import { main } from "./main.ts";
+
+const target = "sample";
+
+Deno.test(`correct possible design count for ${target}`, async () => {
+  const result = await main(target);
+  assertEquals(result.possibleDesigns, 6);
+});
+
+Deno.test(`correct possible design combos for ${target}`, async () => {
+  const result = await main(target);
+  assertEquals(result.possibleDesignCombos, 16);
+});