day 6

2024/6.1.ts

@@ -0,0 +1,81 @@
+import { open } from "node:fs/promises";
+
+const file = await open("./2024/inputs/6");
+
+const map: string[][] = []
+for await (const line of file.readLines()) {
+    map.push(line.split(""))
+}
+
+type Vector2 = {
+    X: number,
+    Y: number
+}
+
+// 0: UP
+// 1: RIGHT
+// 2: DOWN
+// 3: LEFT
+
+const directions: Vector2[] = [{
+    X: 0,
+    Y: -1
+},
+{
+    X: 1,
+    Y: 0
+},
+{
+    X: 0,
+    Y: 1
+},
+{
+    X: -1,
+    Y: 0
+}]
+
+const height = map.length
+const width = map[0].length
+
+let d = 0
+
+const startY = map.findIndex(l => l.includes("^"))
+const startX = map[startY].indexOf("^")
+const position: Vector2 = {
+    X: startX,
+    Y: startY
+}
+
+function getNextCoordinates(): Vector2 {
+    return {
+        X: position.X + directions[d].X,
+        Y: position.Y + directions[d].Y
+    }
+}
+
+function getTile({ X, Y }: Vector2) {
+    if (X < 0 || Y < 0 || X >= width || Y >= height) {
+        return null
+    }
+    return map[Y][X]
+}
+
+function rotate() {
+    d = (d + 1) % 4
+}
+
+function moveForward() {
+    Object.assign(position, getNextCoordinates())
+}
+
+while (getTile(getNextCoordinates())) {
+    const tile = getTile(getNextCoordinates())
+    if (tile == "#") {
+        rotate()
+    } else {
+        moveForward()
+    }
+    map[position.Y][position.X] = "X"
+}
+
+console.log(map.reduce((acc, l) => l.reduce((acc, t) => t == "X" ? acc + 1 : acc, 0) + acc, 0))