2024 day 10

2024/day-10/day10.test.ts

@@ -0,0 +1,40 @@
+import { expect, test } from "bun:test";
+import * as path from "node:path";
+import { part1, part2 } from "./day10.ts";
+
+test("day 10, part 1", async () => {
+	const testInput = await Bun.file(
+		path.resolve(__dirname, "test-input.txt"),
+	).text();
+	const input = await Bun.file(path.resolve(__dirname, "input.txt")).text();
+
+	console.log("\n\n");
+
+	// const testResult = part1(testInput);
+	// console.log("Test data:", testResult);
+	// expect(testResult).toEqual(36);
+
+	const finalResult = part1(input);
+	console.log("Full data:", finalResult);
+	expect(finalResult).toEqual(682);
+
+	console.log("\n\n");
+});
+
+test("day 10, part 2", async () => {
+	const testInput = await Bun.file(
+		path.resolve(__dirname, "test-input.txt"),
+	).text();
+	const input = await Bun.file(path.resolve(__dirname, "input.txt")).text();
+
+	const testResult = part2(testInput);
+	console.log("\n\n");
+	console.log("Test data:", testResult);
+	expect(testResult).toEqual(81);
+
+	const finalResult = part2(input);
+	console.log("Full data:", finalResult);
+	expect(finalResult).toEqual(1511);
+
+	console.log("\n\n");
+});

2024/day-10/day10.ts

@@ -0,0 +1,127 @@
+export function part1(input: string) {
+	let final = 0;
+
+	const trailheads = [];
+	const lines = input.split("\n");
+	const grid = lines.map((l) => l.split("").map(Number));
+	for (let i = 0; i < lines.length; i++) {
+		const line = lines[i];
+		const heights = line.split("").map(Number);
+		for (let j = 0; j < heights.length; j++) {
+			const height = heights[j];
+			if (height === 0) {
+				trailheads.push([i, j]);
+			}
+		}
+	}
+
+	for (const th of trailheads) {
+		const [x, y] = th;
+		const finalPointsReached = [];
+		function foo(path: [number, number][]) {
+			if (path.length === 10) {
+				finalPointsReached.push(path.at(-1));
+				return;
+			}
+			const current = path.at(-1);
+			const currentHeight = path.length - 1;
+
+			if (!current) {
+				throw new Error("must have at least one element");
+			}
+			const prev = path.at(-2);
+			const [pX, pY] = prev ?? [];
+			const [cX, cY] = current;
+			const up = grid[cX - 1]?.[cY];
+			const down = grid[cX + 1]?.[cY];
+			const right = grid[cX]?.[cY + 1];
+			const left = grid[cX]?.[cY - 1];
+			const isPrevUp = pX === cX - 1 && pY === cY;
+			const isPrevDown = pX === cX + 1 && pY === cY;
+			const isPrevRight = pX === cX && pY === cY + 1;
+			const isPrevLeft = pX === cX && pY === cY - 1;
+			if (!isPrevUp && up === currentHeight + 1) {
+				foo([...path, [cX - 1, cY]]);
+			}
+			if (!isPrevDown && down === currentHeight + 1) {
+				foo([...path, [cX + 1, cY]]);
+			}
+			if (!isPrevRight && right === currentHeight + 1) {
+				foo([...path, [cX, cY + 1]]);
+			}
+			if (!isPrevLeft && left === currentHeight + 1) {
+				foo([...path, [cX, cY - 1]]);
+			}
+		}
+		foo([th]);
+		const uniqueFinalPoints = [
+			...new Set(finalPointsReached.map((x) => x.join(","))),
+		].map((x) => x.split(","));
+		final += uniqueFinalPoints.length;
+	}
+	return final;
+}
+export function part2(input: string) {
+	let final = 0;
+
+	const trailheads = [];
+	const lines = input.split("\n");
+	const grid = lines.map((l) => l.split("").map(Number));
+	for (let i = 0; i < lines.length; i++) {
+		const line = lines[i];
+		const heights = line.split("").map(Number);
+		for (let j = 0; j < heights.length; j++) {
+			const height = heights[j];
+			if (height === 0) {
+				trailheads.push([i, j]);
+			}
+		}
+	}
+
+	for (const th of trailheads) {
+		const [x, y] = th;
+		function foo(path: [number, number][]) {
+			if (path.length === 10) {
+				final++;
+				return;
+			}
+			const current = path.at(-1);
+			const currentHeight = path.length - 1;
+
+			if (!current) {
+				throw new Error("must have at least one element");
+			}
+			const prev = path.at(-2);
+			const [pX, pY] = prev ?? [];
+			const [cX, cY] = current;
+			const up = grid[cX - 1]?.[cY];
+			const down = grid[cX + 1]?.[cY];
+			const right = grid[cX]?.[cY + 1];
+			const left = grid[cX]?.[cY - 1];
+			const isPrevUp = pX === cX - 1 && pY === cY;
+			const isPrevDown = pX === cX + 1 && pY === cY;
+			const isPrevRight = pX === cX && pY === cY + 1;
+			const isPrevLeft = pX === cX && pY === cY - 1;
+			if (!isPrevUp && up === currentHeight + 1) {
+				foo([...path, [cX - 1, cY]]);
+			}
+			if (!isPrevDown && down === currentHeight + 1) {
+				foo([...path, [cX + 1, cY]]);
+			}
+			if (!isPrevRight && right === currentHeight + 1) {
+				foo([...path, [cX, cY + 1]]);
+			}
+			if (!isPrevLeft && left === currentHeight + 1) {
+				foo([...path, [cX, cY - 1]]);
+			}
+		}
+		foo([th]);
+	}
+	return final;
+}
+
+function logLines(arr: Array<unknown>) {
+	for (const x of arr) {
+		console.log(x);
+	}
+}

2024/day-10/input.txt

@@ -0,0 +1,54 @@
+034565433432321821235456556798712438943432345432101010
+125674344341210930012367349897601123876501656543238923
+545981265210523841112398232098532014101665437654147014
+436780378019654756501454101123442125012878328956056985
+521091489328765661498760130210356916763969012347841076
+342698456410644570187321221202197809854054521078932987
+434784387569653089298435430143087612870123654169410673
+525601295678762120387589347834561543965434783254321034
+510567856789854871456678956921670123457650199165890321
+654356943889903962345665067830589894398743278056785410
+701245012958712653434784167845678765210634565410156789
+898434321867012344321093254976104543231023876321943089
+686321780154102101287765323987267650122012989423872176
+567980691233283237898894015416398532143606788714565765
+408974500543098946907623234505458545014545698601159854
+312363217632127655416510107612369876105894332589018345
+221457898565634562323421458733478983276701201478121230
+100656967874567641032102369021098744589856782363210121
+789345450923498634543001078112321654678345891054308701
+654212321012654521694210981205430903543232654143489610
+503403430156787610784300870376567812654121743267876523
+012567567343898525695421889487854925780010893210965432
+123498788210123436786438976598943056891234984921014101
+019567699101898345877567887678762147878765675870123012
+108754543210567212968900194589054038969454566767636323
+205610121056750303453213293032123229454323879098545438
+014981232347841219874984782143210110301012978121654569
+123672654338932306705675676154560121212307665430743478
+298543789221069455012310145069430430925408578989832387
+567010176109178764563498232178521567876519454567601296
+432123485458769853074567310123678106898323343218970345
+012034394367458102189601489433439256765401252102181234
+123465210210343012078732676512508349850106769843098321
+054896990101212043896543216109612556743219856784587410
+969887889654302158987894107898743445654340145697656531
+878791078745983467856765545677654354567854234548545621
+745622363215676500345653231987980123498960129639343210
+034215454301876211256570120345678154323870038721658343
+122100189321945308967981011234569067212721801290569012
+543893276430932457898876323233432178008934980387378143
+456764345567801966501895400145567889127645673456269654
+369632105478765873432689312176876901234560012562158765
+278543254309894569546576543089985432321071239873043210
+103450569212723278637434010034394321810980548954560127
+894321078112010198728922121165223010901289687643073438
+765697151003434587017213033278112987874398796542189569
+056788769876524326501304544569001056965834321233675678
+145679458985015415432987693432102345216945610344569547
+230989347034376102341056780540989104307898700123678632
+321078234123289211652346791691071234487465410878766781
+989165106000105690789905882782360943296578321969215690
+076234245612234782349814943485456850123489100154304385
+145210238763145671456723876596306765012101256701235276
+234300149854078980365432101487217898721032349810120123

2024/day-10/test-input.txt

@@ -0,0 +1,8 @@
+89010123
+78121874
+87430965
+96549874
+45678903
+32019012
+01329801
+10456732