solve Day08 in JS/TS

Day08/js/solution.js

@@ -0,0 +1,82 @@
+const fs = require('fs');
+const path = require('path');
+
+function gcd(a, b) {
+    while (b !== 0) {
+        let t = b;
+        b = a % b;
+        a = t;
+    }
+    return a;
+}
+
+function lcm(a, b) {
+    return (a * b) / gcd(a, b);
+}
+
+function parseFile(filePath) {
+    console.log(`Parsing file: ${filePath}`);
+    const data = fs.readFileSync(filePath, 'utf8').trim();
+    const [stepsSection, rulesSection] = data.split('\n\n');
+    const steps = stepsSection.split('').map(char => char === 'L' ? 0 : 1);
+    const rules = rulesSection.split('\n').reduce((acc, line) => {
+        const [state, directions] = line.split('=').map(s => s.trim());
+        const [left, right] = directions.split(',').map(s => s.trim());
+        acc['L'][state] = left.slice(1);
+        acc['R'][state] = right.slice(0, -1);
+        return acc;
+    }, { 'L': {}, 'R': {} });
+
+    return { steps, rules };
+}
+
+function navigateNetworkSimultaneously(steps, rules) {
+    console.log("Starting navigation of network.");
+    const startNodes = Object.keys(rules['L']).filter(node => node.endsWith('A'));
+    let currentNodes = startNodes;
+    let stepCount = 0;
+    const timeToZ = {};
+
+    while (Object.keys(timeToZ).length < startNodes.length) {
+        currentNodes.forEach((node, index) => {
+            const direction = steps[stepCount % steps.length] === 0 ? 'L' : 'R';
+            const nextNode = rules[direction][node];
+            currentNodes[index] = nextNode;
+            if (nextNode.endsWith('Z') && !(index in timeToZ)) {
+                timeToZ[index] = stepCount + 1;
+            }
+        });
+        stepCount++;
+        console.log(`Step ${stepCount}: Current nodes - ${currentNodes}`);
+    }
+
+    return Object.values(timeToZ).reduce((acc, val) => lcm(acc, val), 1);
+}
+
+function runTest() {
+    console.log("Running test...");
+    const testPath = path.join(__dirname, '../test.txt');
+    const { steps, rules } = parseFile(testPath);
+    const expected = 6;
+    const result = navigateNetworkSimultaneously(steps, rules);
+
+    if (result !== expected) {
+        throw new Error(`Test failed: expected ${expected}, got ${result}`);
+    }
+
+    console.log(`Test passed with ${result} steps.`);
+}
+
+function main() {
+    try {
+        runTest();
+        const inputPath = path.join(__dirname, '../input.txt');
+        const { steps, rules } = parseFile(inputPath);
+        const result = navigateNetworkSimultaneously(steps, rules);
+        console.log(`All paths reached 'Z' nodes simultaneously in ${result} steps.`);
+    } catch (error) {
+        console.error(`Error: ${error.message}`);
+    }
+}
+
+main();

Day08/ts/solution.ts

@@ -0,0 +1,82 @@
+import * as fs from 'fs';
+import * as path from 'path';
+
+function gcd(a: number, b: number): number {
+    while (b !== 0) {
+        let t = b;
+        b = a % b;
+        a = t;
+    }
+    return a;
+}
+
+function lcm(a: number, b: number): number {
+    return (a * b) / gcd(a, b);
+}
+
+function parseFile(filePath: string): { steps: number[], rules: { [key: string]: { [key: string]: string } } } {
+    console.log(`Parsing file: ${filePath}`);
+    const data = fs.readFileSync(filePath, 'utf8').trim();
+    const [stepsSection, rulesSection] = data.split('\n\n');
+    const steps = stepsSection.split('').map((char: string) => char === 'L' ? 0 : 1);
+    const rules = rulesSection.split('\n').reduce((acc: { [key: string]: { [key: string]: string } }, line: string) => {
+        const [state, directions] = line.split('=').map((s: string) => s.trim());
+        const [left, right] = directions.split(',').map((s: string) => s.trim());
+        acc['L'][state] = left.slice(1);
+        acc['R'][state] = right.slice(0, -1);
+        return acc;
+    }, { 'L': {}, 'R': {} });
+
+    return { steps, rules };
+}
+
+function navigateNetworkSimultaneously(steps: number[], rules: { [key: string]: { [key: string]: string } }): number {
+    console.log("Starting navigation of network.");
+    const startNodes = Object.keys(rules['L']).filter((node: string) => node.endsWith('A'));
+    let currentNodes = startNodes;
+    let stepCount = 0;
+    const timeToZ: { [key: number]: number } = {};
+
+    while (Object.keys(timeToZ).length < startNodes.length) {
+        currentNodes.forEach((node: string, index: number) => {
+            const direction = steps[stepCount % steps.length] === 0 ? 'L' : 'R';
+            const nextNode = rules[direction][node];
+            currentNodes[index] = nextNode;
+            if (nextNode.endsWith('Z') && !(index in timeToZ)) {
+                timeToZ[index] = stepCount + 1;
+            }
+        });
+        stepCount++;
+        console.log(`Step ${stepCount}: Current nodes - ${currentNodes}`);
+    }
+
+    return Object.values(timeToZ).reduce((acc: number, val: number) => lcm(acc, val), 1);
+}
+
+function runTest(): void {
+    console.log("Running test...");
+    const testPath = path.join(__dirname, '../test.txt');
+    const { steps, rules } = parseFile(testPath);
+    const expected = 6;
+    const result = navigateNetworkSimultaneously(steps, rules);
+
+    if (result !== expected) {
+        throw new Error(`Test failed: expected ${expected}, got ${result}`);
+    }
+
+    console.log(`Test passed with ${result} steps.`);
+}
+
+function main(): void {
+    try {
+        runTest();
+        const inputPath = path.join(__dirname, '../input.txt');
+        const { steps, rules } = parseFile(inputPath);
+        const result = navigateNetworkSimultaneously(steps, rules);
+        console.log(`All paths reached 'Z' nodes simultaneously in ${result} steps.`);
+    } catch (error: any) {
+        console.error(`Error: ${error.message}`);
+    }
+}
+
+main();

package-lock.json

@@ -9,6 +9,7 @@
       "version": "1.0.0",
       "license": "ISC",
       "dependencies": {
+        "@types/node": "^20.10.4",
         "fs": "^0.0.1-security"
       },
       "devDependencies": {
@@ -156,6 +157,14 @@
       "integrity": "sha512-5+fP8P8MFNC+AyZCDxrB2pkZFPGzqQWUzpSeuuVLvm8VMcorNYavBqoFcxK8bQz4Qsbn4oUEEem4wDLfcysGHA==",
       "dev": true
     },
+    "node_modules/@types/node": {
+      "version": "20.10.4",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-20.10.4.tgz",
+      "integrity": "sha512-D08YG6rr8X90YB56tSIuBaddy/UXAA9RKJoFvrsnogAum/0pmjkgi4+2nx96A330FmioegBWmEYQ+syqCFaveg==",
+      "dependencies": {
+        "undici-types": "~5.26.4"
+      }
+    },
     "node_modules/@types/semver": {
       "version": "7.5.6",
       "resolved": "https://registry.npmjs.org/@types/semver/-/semver-7.5.6.tgz",
@@ -1519,6 +1528,11 @@
         "node": ">=14.17"
       }
     },
+    "node_modules/undici-types": {
+      "version": "5.26.5",
+      "resolved": "https://registry.npmjs.org/undici-types/-/undici-types-5.26.5.tgz",
+      "integrity": "sha512-JlCMO+ehdEIKqlFxk6IfVoAUVmgz7cU7zD/h9XZ0qzeosSHmUJVOzSQvvYSYWXkFXC+IfLKSIffhv0sVZup6pA=="
+    },
     "node_modules/uri-js": {
       "version": "4.4.1",
       "resolved": "https://registry.npmjs.org/uri-js/-/uri-js-4.4.1.tgz",

package.json

@@ -17,6 +17,7 @@
     "eslint": "^8.55.0"
   },
   "dependencies": {
+    "@types/node": "^20.10.4",
     "fs": "^0.0.1-security"
   }
 }

tsconfig.json

@@ -1,6 +1,6 @@
 {
     "compilerOptions": {
-        "target": "es5",
+        "target": "ES2023",
         "module": "commonjs",
         "strict": true,
         "esModuleInterop": true