2024D23: part 1

Author: martapanc

2024/src/2024/day23/day23.test.ts

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+import {part1, part2} from "./day23";
+
+describe('2024 Day 23', () => {
+    test('Part 1', async () => {
+        expect(await part1('testInput1')).toEqual(7);
+        expect(await part1('input')).toEqual(1238);
+    });
+
+    test('Part 2', async () => {
+        expect(await part2('testInput1')).toEqual(31);
+        expect(await part2('input')).toEqual(29379307);
+    });
+});

2024/src/2024/day23/day23.ts

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+import path from "node:path";
+import {readInputLineByLine} from "@utils/io";
+
+export async function part1(inputFile: string) {
+    return await day23(inputFile, findComputerTriplets);
+}
+
+export async function part2(inputFile: string) {
+    return await day23(inputFile);
+}
+
+async function day23(inputFile: string, calcFn?: (lines: string[]) => number) {
+    const inputPath = path.join(__dirname, inputFile);
+    const lines = await readInputLineByLine(inputPath);
+
+    return calcFn?.(lines);
+}
+
+function findComputerTriplets(lines: string[]) {
+    const adjacencyList: { [key: string]: Set<string>} = {};
+    for (const connection of lines) {
+        const [a, b] = connection.split("-");
+        if (!adjacencyList[a])
+            adjacencyList[a] = new Set();
+        if (!adjacencyList[b])
+            adjacencyList[b] = new Set();
+
+        adjacencyList[a].add(b);
+        adjacencyList[b].add(a);
+    }
+
+    const triangles: Set<string> = new Set();
+    let trianglesStartingWithT = 0;
+    for (const [node, neighbors] of Object.entries(adjacencyList)) {
+        const neighborsArray = Array.from(neighbors);
+
+        for (let i = 0; i < neighborsArray.length; i++) {
+            for (let j = i + 1; j < neighborsArray.length; j++) {
+                const neighborA = neighborsArray[i];
+                const neighborB = neighborsArray[j];
+
+                if (adjacencyList[neighborA].has(neighborB)) {
+                    const triangle = [node, neighborA, neighborB].sort().join(",");
+                    triangles.add(triangle);
+                }
+            }
+        }
+    }
+
+    [...triangles].forEach((triangle: string) => {
+        const split = triangle.split(",")
+        if (split.some(s => s.startsWith("t"))) {
+            trianglesStartingWithT++;
+        }
+    })
+
+    return trianglesStartingWithT;
+}

2024/src/2024/day23/testInput1

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+kh-tc
+qp-kh
+de-cg
+ka-co
+yn-aq
+qp-ub
+cg-tb
+vc-aq
+tb-ka
+wh-tc
+yn-cg
+kh-ub
+ta-co
+de-co
+tc-td
+tb-wq
+wh-td
+ta-ka
+td-qp
+aq-cg
+wq-ub
+ub-vc
+de-ta
+wq-aq
+wq-vc
+wh-yn
+ka-de
+kh-ta
+co-tc
+wh-qp
+tb-vc
+td-yn