2024 day 16 part 1

2024/day-16/maze.ts

@@ -0,0 +1,52 @@
+import { PriorityQueue } from "@datastructures-js/priority-queue"
+
+type Point = [number, number]
+type OhGod = [number, number, number, number, number]
+export function solveMaze(maze: string[][]): number {
+	const rows = maze.length
+	const cols = maze[0].length
+	let start: Point | null = null
+
+	for (let r = 0; r < rows; r++) {
+		for (let c = 0; c < cols; c++) {
+			const char = maze[r][c]
+			if (char === "S") {
+				start = [r, c]
+				break
+			}
+		}
+		if (start) {
+			break
+		}
+	}
+	if (!start) throw Error("fuck")
+	const queue = new PriorityQueue<OhGod>((a, b) => a[0] - b[0])
+
+	queue.enqueue([0, start[0], start[1], 0, 1])
+
+	const seen = new Set<string>([stringify(start[0], start[1], 0, 1)])
+
+	while (!queue.isEmpty()) {
+		const [cost, r, c, dr, dc] = queue.dequeue()
+		seen.add(stringify(r, c, dr, dc))
+		if (maze[r][c] === "E") {
+			return cost
+		}
+		const options: OhGod[] = [
+			[cost + 1, r + dr, c + dc, dr, dc],
+			[cost + 1000, r, c, dc, -dr],
+			[cost + 1000, r, c, -dc, dr],
+		]
+		for (const [ncost, nr, nc, ndr, ndc] of options) {
+			if (maze[nr][nc] === "#" || seen.has(stringify(nr, nc, ndr, ndc))) {
+				continue
+			}
+			queue.enqueue([ncost, nr, nc, ndr, ndc])
+		}
+	}
+	throw Error("shit")
+}
+
+function stringify(v1: number, v2: number, v3: number, v4: number) {
+	return `${v1},${v2},${v3},${v4}`
+}