day 06 part 1 finished

2024/06/index.js

@@ -0,0 +1,73 @@
+import fs from 'node:fs'
+
+let map = []
+function init(filename) {
+    const data = fs.readFileSync(filename, { encoding: 'utf-8' }, data => data)
+    map = data.split('\n')
+    const guard = new Guard()
+    guard.position = guard.find()
+
+    console.log(`guard is at ${guard.position}`)
+    guard.solve1()
+}
+
+class Guard {
+    constructor() {
+        this.position = [0, 0]
+        this.visited = []
+        this.dir = [-1, 0] // y, x - looking up
+        this.steps = 0
+    }
+    rotate() {
+        const [y, x] = this.dir
+        if (y === -1 && x === 0) { console.log(`going right`); this.dir = [0, 1] }
+        if (y === 0 && x === 1) { console.log(`going down`); this.dir = [1, 0] }
+        if (y === 1 && x === 0) { console.log(`going left`); this.dir = [0, -1] }
+        if (y === 0 && x === -1) { console.log(`going up`); this.dir = [-1, 0] }
+        return this.dir
+    }
+    find() {
+        for (let y = 0; y < map.length; y++) {
+            for (let x = 0; x < map[y].length; x++) {
+                if (map[y][x] === "^") return [y, x]
+            }
+        }
+    }
+    goStraight() {
+        const [y, x] = this.position
+        const [dy, dx] = this.dir
+        this.position = [y + dy, x + dx]
+        //const iWasAlreadyHere = this.visited.some(visits => visits.split()[0] === y + dy && visits.split()[1] === x + dx)
+        if (!this.visited.includes(this.position)) this.visited.push(this.position)
+
+        this.steps += 1
+
+    }
+    isLeaving() {
+        const [y, x] = this.position
+        const [dy, dx] = this.dir
+        return x + dx < 0 || x + dx > map[0].length || y + dy < 0 || y + dy >= map.length
+    }
+    isBlockAhead() {
+        const [y, x] = this.position
+        const [dy, dx] = this.dir
+        return map[y + dy][x + dx] === "#" ? true : false
+    }
+    isStillOnMap() {
+        const [y, x] = this.position
+        return (y >= 0 && y <= map.length) && (x >= 0 && x <= map[0].length)
+    }
+    solve1() {
+        console.log("y", map.length, "x", map[0].length)
+        this.visited = [this.position]
+        while (this.isStillOnMap()) {
+            if (this.isLeaving()) { console.log(`ran ${this.steps} steps`); break }
+            if (this.isBlockAhead()) this.rotate()
+            this.goStraight(this.dir)
+        }
+        this.visited = Array.from(new Set(this.visited.map(JSON.stringify)), JSON.parse);
+        console.log(this.visited.length)
+    }
+}
+
+init('input.txt')