add 8

8.1.ts

@@ -0,0 +1,51 @@
+import { open } from 'node:fs/promises';
+
+
+const file = await open('./inputs/8');
+let sum = 0
+let index = -1
+let path = ""
+
+const nodes: { [key: string]: { L: string, R: string } } = {}
+
+for await (const line of file.readLines()) {
+    index++
+    if (index === 0) {
+        path = line
+        continue
+    }
+    if (line.length === 0) {
+        continue
+    }
+
+    const result = /^(?<node>\w+) = \((?<L>\w+), (?<R>\w+)\)/gms.exec(line)
+    if (result === null) {
+        throw new Error('wtf')
+    }
+    if (result.groups === undefined) {
+        throw new Error('wtf')
+    }
+
+    const node = result.groups['node']
+    const L = result.groups['L']
+    const R = result.groups['R']
+
+    nodes[node] = { L, R }
+}
+
+let step = 0
+let current = 'AAA'
+while (current !== 'ZZZ') {
+    let direction = path.at(step % path.length) as 'L' | 'R'
+    current = nodes[current][direction]
+    step++
+}
+console.log(path)
+
+
+
+
+
+console.log(step)
+
+

8.2.ts

@@ -0,0 +1,46 @@
+import { open } from 'node:fs/promises';
+
+
+const file = await open('./inputs/8');
+let index = -1
+let path = ""
+
+const nodes: { [key: string]: { L: string, R: string } } = {}
+
+for await (const line of file.readLines()) {
+    index++
+    if (index === 0) {
+        path = line
+        continue
+    }
+    if (line.length === 0) {
+        continue
+    }
+
+    const result = /^(?<node>\w+) = \((?<L>\w+), (?<R>\w+)\)/gms.exec(line)
+    if (result === null) {
+        throw new Error('wtf')
+    }
+    if (result.groups === undefined) {
+        throw new Error('wtf')
+    }
+
+    const node = result.groups['node']
+    const L = result.groups['L']
+    const R = result.groups['R']
+
+    nodes[node] = { L, R }
+}
+
+let currents = Object.keys(nodes).filter(e => e.endsWith('A'))
+let currentSteps = currents.map(n => {
+    let step = 0
+    while (!n.endsWith('Z')) {
+        let direction = path.at(Number(step % path.length)) as 'L' | 'R'
+        n = nodes[n][direction]
+        step++
+    }
+    return step
+})
+
+console.log(currentSteps)

inputs/8.example

@@ -0,0 +1,10 @@
+LR
+
+11A = (11B, XXX)
+11B = (XXX, 11Z)
+11Z = (11B, XXX)
+22A = (22B, XXX)
+22B = (22C, 22C)
+22C = (22Z, 22Z)
+22Z = (22B, 22B)
+XXX = (XXX, XXX)