day 08 part 2 finished

2023/day08/example.txt

@@ -1,5 +1,10 @@
-LLR
+LR
 
-AAA = (BBB, BBB)
-BBB = (AAA, ZZZ)
-ZZZ = (ZZZ, ZZZ)
+11A = (11B, XXX)
+11B = (XXX, 11Z)
+11Z = (11B, XXX)
+22A = (22B, XXX)
+22B = (22C, 22C)
+22C = (22Z, 22Z)
+22Z = (22B, 22B)
+XXX = (XXX, XXX)

2023/day08/index.js

@@ -6,50 +6,61 @@ function init(filename) {
         data.split('\n\n')[0].split(''),
         data.split('\n\n')[1]
     )
-    desertmap.navigate()
+    desertmap.navigate_ghosts()
 }
 
 
 class DesertMap {
     instructions = []
     map = ""
-    #iterator
     #route = []
-    #way = null
     constructor(instructions, map) {
 
         this.instructions = instructions
         this.map = map
         this.#route = []
-        this.#iterator = 0
         this.steps = 0
-        this.#way = null
     }
     setup() {
         const matches = [...this.map.matchAll(/(\w+) = \((\w+), (\w+)\)/gm)]
         matches.forEach(match => {
-            this.#route.push({ goal: match[1], L: match[2], R: match[3] })
+            this.#route.push({ from: match[1], L: match[2], R: match[3] })
         })
     }
-    run(towards) {
-        if (!this.steps) {
-            return this.#route.find(route => route.goal === 'AAA')[towards]
+    run(towards, from) {
+        if (!this.steps && !from) {
+            return this.#route.find(route => route.from === 'AAA')[towards]
         }
-        return this.#route.find(route => route.goal === this.#way)[towards]
+        return this.#route.find(route => route.from === from)[towards]
     }
+    navigate_ghosts() {
+        this.setup()
+        let i = 0
+        let start = this.#route.filter(route => route.from[2] === 'A')
+            .map(route => route.from)
+        while (i < this.instructions.length | true) {
+            start = start.map(route => this.run(this.instructions[i], route))
+            ++this.steps
+            if (start.filter(route => route[2] === 'Z').length === start.length) {
+                console.log(this.steps)
+                return true
+            }
+            i = this.instructions.length - i === 1 ? 0 : i + 1
+        }
+        console.log(this.steps + 1)
+    }
+
     navigate() {
         this.setup()
-        //console.log(this.#route)
-
-        while (this.#iterator < this.instructions.length | true) {
-            this.#way = this.run(this.instructions[this.#iterator])
-            this.steps += 1
-            console.log(this.#iterator, this.#way, this.steps)
-            if (this.#way === 'ZZZ') { return false }
-            this.#iterator = this.instructions.length - this.#iterator === 1 ? 0 : this.#iterator + 1
+        let i = 0
+        while (i < this.instructions.length | true) {
+            let from = this.run(this.instructions[i], from)
+            ++this.steps
+            console.log(i, from, this.steps)
+            if (from === 'ZZZ') { return false }
+            i = this.instructions.length - i === 1 ? 0 : i + 1
         }
         console.log(this.steps)
-
     }
 }