feat: solved 2023 day 9

.github/badges/typescript/2023.json

@@ -1,6 +1,6 @@
 {
 	"schemaVersion": 1,
 	"label": "Advent of TypeScript 2023",
-	"message": "7/25",
+	"message": "8/25",
 	"color": "orange"
 }

resources/2023/09/example.1.txt

@@ -0,0 +1,3 @@
+0 3 6 9 12 15
+1 3 6 10 15 21
+10 13 16 21 30 45

solutions/typescript/2023/08/package.json

@@ -61,6 +61,11 @@
 			"import": "./dist/p2.js",
 			"default": "./dist/p2.js"
 		},
+		"./parse": {
+			"types": "./src/parse.ts",
+			"import": "./dist/parse.js",
+			"default": "./dist/parse.js"
+		},
 		"./readme": "./readme.md"
 	},
 	"dependencies": {

solutions/typescript/2023/09/src/p1.spec.ts

@@ -7,14 +7,14 @@ describe('2023 09 p1', () => {
 	describe('the input', () => {
 		it('should solve the input', async () => {
 			const resources = await loadTaskResources(packageJson.aoc);
-			expect(p1(resources.input)).toEqual(0);
+			expect(p1(resources.input)).toEqual(1_938_731_307);
 		});
 	});
 
 	describe('example 1', () => {
 		it('should be solved', async () => {
 			const resources = await loadTaskResources(packageJson.aoc, 'example.1.txt');
-			expect(p1(resources.input)).toEqual(0);
+			expect(p1(resources.input)).toEqual(114);
 		});
 	});
 });

solutions/typescript/2023/09/src/p1.ts

@@ -1,8 +1,21 @@
 import { task } from '@alexaegis/advent-of-code-lib';
 import packageJson from '../package.json';
+import { extrapolateSequence, parse } from './parse.js';
 
-export const p1 = (_input: string): number => {
-	return 0;
+const extrapolateNextInStack = (sequenceStack: number[][]): number[][] => {
+	let carry = sequenceStack.last().last();
+	for (let i = sequenceStack.length - 1; i >= 0; i--) {
+		carry = (sequenceStack[i]?.last() ?? 0) + carry;
+		sequenceStack[i]?.push(carry);
+	}
+	return sequenceStack;
 };
 
-await task(p1, packageJson.aoc); // 0 ~0ms
+export const p1 = (input: string): number =>
+	parse(input)
+		.map(extrapolateSequence)
+		.map(extrapolateNextInStack)
+		.map((extrapolatedStack) => extrapolatedStack.first().last())
+		.sum();
+
+await task(p1, packageJson.aoc); // 1938731307 ~1.57ms

solutions/typescript/2023/09/src/p2.spec.ts

@@ -7,14 +7,14 @@ describe('2023 09 p2', () => {
 	describe('the input', () => {
 		it('should solve the input', async () => {
 			const { input } = await loadTaskResources(packageJson.aoc);
-			expect(p2(input)).toEqual(0);
+			expect(p2(input)).toEqual(948);
 		});
 	});
 
 	describe('example 1', () => {
 		it('should be solved', async () => {
 			const { input } = await loadTaskResources(packageJson.aoc, 'example.1.txt');
-			expect(p2(input)).toEqual(0);
+			expect(p2(input)).toEqual(2);
 		});
 	});
 });

solutions/typescript/2023/09/src/p2.ts

@@ -1,8 +1,21 @@
 import { task } from '@alexaegis/advent-of-code-lib';
 import packageJson from '../package.json';
+import { extrapolateSequence, parse } from './parse.js';
 
-export const p2 = (_input: string): number => {
-	return 0;
+const extrapolatePreviousInStack = (sequenceStack: number[][]): number[][] => {
+	let carry = sequenceStack.last().first();
+	for (let i = sequenceStack.length - 1; i >= 0; i--) {
+		carry = (sequenceStack[i]?.first() ?? 0) - carry;
+		sequenceStack[i]?.unshift(carry);
+	}
+	return sequenceStack;
 };
 
-await task(p2, packageJson.aoc); // 0 ~0ms
+export const p2 = (input: string): number =>
+	parse(input)
+		.map(extrapolateSequence)
+		.map(extrapolatePreviousInStack)
+		.map((extrapolatedStack) => extrapolatedStack.first().first())
+		.sum();
+
+await task(p2, packageJson.aoc); // 948 ~1.62ms

solutions/typescript/2023/09/src/parse.ts

@@ -0,0 +1,15 @@
+export const parse = (input: string): number[][] =>
+	input.lines(false).map((line) => line.splitToInt());
+
+export const extrapolateSequence = (sequence: number[]): number[][] => {
+	const sequenceStack: number[][] = [sequence];
+	while (sequenceStack.last().some((i) => i !== 0)) {
+		sequenceStack.push(
+			sequenceStack
+				.last()
+				.slideWindow(2, 1)
+				.map(([left, right]) => right - left),
+		);
+	}
+	return sequenceStack;
+};

solutions/typescript/readme.md

@@ -16,7 +16,7 @@
 | [Day 6](/solutions/typescript/2023/06/) | [40μs](/solutions/typescript/2023/06/src/p1.ts)    | [7μs](/solutions/typescript/2023/06/src/p2.ts)     |
 | [Day 7](/solutions/typescript/2023/07/) | [8.70ms](/solutions/typescript/2023/07/src/p1.ts)  | [20.46ms](/solutions/typescript/2023/07/src/p2.ts) |
 | [Day 8](/solutions/typescript/2023/08/) | [10.25ms](/solutions/typescript/2023/08/src/p1.ts) | [11.44ms](/solutions/typescript/2023/08/src/p2.ts) |
-| Day 9                                   | -                                                  | -                                                  |
+| [Day 9](/solutions/typescript/2023/09/) | [1.57ms](/solutions/typescript/2023/09/src/p1.ts)  | [1.62ms](/solutions/typescript/2023/09/src/p2.ts)  |
 | Day 10                                  | -                                                  | -                                                  |
 | Day 11                                  | -                                                  | -                                                  |
 | Day 12                                  | -                                                  | -                                                  |