advent_of_code_2023/Day12/ts/solution.ts
2023-12-12 20:43:09 +01:00

91 lines
2.7 KiB
TypeScript

import * as fs from 'fs';
import * as path from 'path';
function readData(filePath: string): string[] {
try {
return fs.readFileSync(filePath, 'utf8').trim().split('\n');
} catch (error) {
console.error(`Error reading file '${filePath}': ${(error as Error).message}`);
process.exit(1);
}
}
function unfoldRecord(record: string): [string, number[]] {
let [dots] = record.split(' ');
const [, blockStr] = record.split(' ');
dots = Array(5).fill(dots).join('?');
const blocks = blockStr.split(',').map(Number);
const unfoldedBlocks = Array(5).fill(blocks).flat();
return [dots, unfoldedBlocks];
}
function countArrangements(dots: string, blocks: number[], i: number = 0, bi: number = 0, current: number = 0, memo: Record<string, number> = {}): number {
const key = `${i},${bi},${current}`;
if (key in memo) {
return memo[key];
}
if (i === dots.length) {
if (bi === blocks.length && current === 0) {
return 1;
} else if (bi === blocks.length - 1 && blocks[bi] === current) {
return 1;
} else {
return 0;
}
}
let ans = 0;
for (const c of ['.', '#']) {
if (dots[i] === c || dots[i] === '?') {
if (c === '.') {
if (current === 0) {
ans += countArrangements(dots, blocks, i + 1, bi, 0, memo);
} else if (current > 0 && bi < blocks.length && blocks[bi] === current) {
ans += countArrangements(dots, blocks, i + 1, bi + 1, 0, memo);
}
} else if (c === '#') {
ans += countArrangements(dots, blocks, i + 1, bi, current + 1, memo);
}
}
}
memo[key] = ans;
return ans;
}
function solvePuzzle(lines: string[]): number {
let total = 0;
for (const line of lines) {
console.log(`Processing: ${line}`);
const [dots, blocks] = unfoldRecord(line);
total += countArrangements(dots, blocks);
}
return total;
}
function testPuzzle(): void {
console.log("Running tests...");
const testLines = readData(path.join(__dirname, '../test.txt'));
const testResult = solvePuzzle(testLines);
console.log(`Test result: ${testResult}`);
if (testResult !== 525152) {
throw new Error("Test failed!");
}
console.log("Test passed.");
}
function main(): void {
try {
testPuzzle();
const inputLines = readData(path.join(__dirname, '../input.txt'));
console.log("Processing input data...");
const result = solvePuzzle(inputLines);
console.log(`Final result: ${result}`);
} catch (error) {
console.error(`An error occurred: ${(error as Error).message}`);
}
}
main();