feat: solved 2023 day 12 part 2

AlexAegis · Dec 13, 2023 · 9d32174 · 9d32174
1 parent e75a7bf
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Showing 4 changed files with 167 additions and 63 deletions.
diff --git a/resources/2023/12/example.2.txt b/resources/2023/12/example.2.txt
@@ -0,0 +1 @@
+#??????.??.??? 4,1,1,1
diff --git a/solutions/typescript/2023/12/src/p1.ts b/solutions/typescript/2023/12/src/p1.ts
@@ -1,38 +1,17 @@
 import { cartesianCombinations, task } from '@alexaegis/advent-of-code-lib';
 import packageJson from '../package.json';
-
-interface SprintLog {
-	/**
-	 * `?` unknown
-	 * `.` operational
-	 * `#` damaged
-	 */
-	log: string;
-	criteria: number[];
-	criteriaRegExp: RegExp;
-}
-
-export const criteriaToRegExp = (criteria: number[]): RegExp =>
-	new RegExp('^\\.*' + criteria.map((brokenCount) => `#{${brokenCount}}`).join('\\.+') + '\\.*$');
+import { parse } from './parse.js';
 
 function generateVariations(damagedLog: string, criteria: RegExp): string[] {
 	const variants = [...damagedLog].map((entry) => (entry === '?' ? ['#', '.'] : [entry]));
-	// const variationCount = variants.map((ev) => ev.length).product();
 	return cartesianCombinations(...variants)
 		.map((combination) => combination.join(''))
 		.filter((combination) => criteria.test(combination));
 }
 
 export const p1 = (input: string): number =>
-	input
-		.lines(false)
-		.map((line) => {
-			const [log, critRaw] = line.splitIntoStringPair(' ');
-			const crit = critRaw.splitToInt({ delimiter: /,/ });
-			return { log, criteria: crit, criteriaRegExp: criteriaToRegExp(crit) } as SprintLog;
-		})
+	parse(input)
 		.map((spring) => generateVariations(spring.log, spring.criteriaRegExp).length)
-
 		.sum();
 
 await task(p1, packageJson.aoc); // 7118 ~0ms
diff --git a/solutions/typescript/2023/12/src/p2.ts b/solutions/typescript/2023/12/src/p2.ts
@@ -1,51 +1,150 @@
 import { task } from '@alexaegis/advent-of-code-lib';
 import packageJson from '../package.json';
+import { parse, type SpringLog } from './parse.js';
 
-interface SprintLog {
-	/**
-	 * `?` unknown
-	 * `.` operational
-	 * `#` damaged
-	 */
-	log: string;
-	criteria: number[];
-	criteriaRegExp: RegExp;
+interface State {
+	rebuiltLog: string;
+	currentCriteria: number;
+	currentOriginalCriteria: number;
+	remainingDamagedLog: string;
+	remainingCriteria: number[];
 }
 
-export const criteriaToRegExp = (criteria: number[]): RegExp =>
-	new RegExp('^\\.*' + criteria.map((brokenCount) => `#{${brokenCount}}`).join('\\.+') + '\\.*$');
+const calculateVariations = (state: State, cache: Map<string, number>): number => {
+	const key =
+		state.remainingCriteria.join(',') +
+		';' +
+		state.remainingDamagedLog +
+		';' +
+		state.currentOriginalCriteria +
+		';' +
+		state.currentCriteria;
 
-function calculateVariations(damagedLog: string, criteria: number[]): number {
-	const totalVariationCount = [...damagedLog].map((entry) => (entry === '?' ? 2 : 1)).product();
-	const minlen = criteria.sum() + criteria.length - 1;
-	// const variationCount = variants.map((ev) => ev.length).product();
-	return totalVariationCount ^ minlen;
-}
+	const cachedResult = cache.get(key);
+	if (cachedResult !== undefined) {
+		return cachedResult;
+	}
+
+	let result = cachedResult ?? 0;
+
+	while (state.currentCriteria > 0 && state.remainingDamagedLog.startsWith('#')) {
+		state.currentCriteria = state.currentCriteria - 1;
+		state.remainingDamagedLog = state.remainingDamagedLog.slice(1);
+		state.rebuiltLog = state.rebuiltLog + '#';
+	}
+
+	if (
+		state.currentCriteria === 0 &&
+		state.remainingCriteria.length === 0 &&
+		!state.remainingDamagedLog.includes('#')
+	) {
+		state.rebuiltLog += state.remainingDamagedLog.replaceAll('?', '.');
+		return 1;
+	}
+
+	while (
+		state.currentCriteria === state.currentOriginalCriteria &&
+		state.remainingDamagedLog.startsWith('.')
+	) {
+		state.remainingDamagedLog = state.remainingDamagedLog.slice(1);
+		state.rebuiltLog = state.rebuiltLog + '.';
+	}
+
+	if (state.currentCriteria > 0 && state.remainingDamagedLog.startsWith('.')) {
+		return 0;
+	}
+
+	if (state.currentCriteria === 0 && state.remainingDamagedLog.startsWith('#')) {
+		return 0;
+	}
+
+	if (
+		state.currentCriteria === 0 &&
+		(state.remainingDamagedLog.startsWith('.') || state.remainingDamagedLog.startsWith('?'))
+	) {
+		const nextCriteria = state.remainingCriteria.shift();
+
+		if (nextCriteria === undefined) {
+			state.currentOriginalCriteria = 0;
+		} else {
+			state.currentCriteria = nextCriteria;
+			state.currentOriginalCriteria = nextCriteria;
+		}
+
+		state.rebuiltLog = state.rebuiltLog + '.';
+		state.remainingDamagedLog = state.remainingDamagedLog.slice(1);
+	}
+
+	while (
+		state.currentCriteria === state.currentOriginalCriteria &&
+		state.remainingDamagedLog.startsWith('.')
+	) {
+		state.remainingDamagedLog = state.remainingDamagedLog.slice(1);
+		state.rebuiltLog = state.rebuiltLog + '.';
+	}
+
+	if (
+		state.currentCriteria === 0 &&
+		state.remainingDamagedLog.length === 0 &&
+		state.remainingCriteria.length === 0
+	) {
+		return 1;
+	}
+
+	if (state.remainingDamagedLog.startsWith('?')) {
+		result += calculateVariations(
+			{
+				...state,
+				remainingCriteria: [...state.remainingCriteria],
+				remainingDamagedLog: '#' + state.remainingDamagedLog.slice(1),
+			},
+			cache,
+		);
+
+		result += calculateVariations(
+			{
+				...state,
+				remainingCriteria: [...state.remainingCriteria],
+				remainingDamagedLog: '.' + state.remainingDamagedLog.slice(1),
+			},
+			cache,
+		);
+	} else if (state.currentCriteria > 0 && state.remainingDamagedLog.length > 0) {
+		result += calculateVariations(state, cache);
+	}
+	cache.set(key, result);
+	return result;
+};
+
+const unfoldEntry =
+	(times: number) =>
+	(entry: SpringLog): SpringLog => ({
+		...entry,
+		log: Array.from({ length: times })
+			.map(() => entry.log)
+			.join('?'),
+		criteria: Array.from({ length: times }).flatMap(() => entry.criteria),
+	});
 
 export const p2 = (input: string): number =>
-	input
-		.lines(false)
-
-		.map((line) => {
-			console.log(line);
-			const [log, critRaw] = line.splitIntoStringPair(' ');
-			const crit = critRaw.splitToInt({ delimiter: /,/ });
-			//crit = Array.from({ length: 5 }).flatMap(() => crit);
-			const multipliedLog = log;
-			//multipliedLog = Array.from({ length: 5 })
-			//	.map(() => log)
-			//	.join('?');
-			return {
-				log: multipliedLog,
-				criteria: crit,
-				criteriaRegExp: criteriaToRegExp(crit),
-			} as SprintLog;
+	parse(input)
+		.map(unfoldEntry(5))
+		.map((entry) => {
+			const [currentCriteria, ...remainingCriteria] = entry.criteria;
+			if (!currentCriteria) {
+				throw new Error('no criteria for line');
+			}
+			return calculateVariations(
+				{
+					currentCriteria,
+					currentOriginalCriteria: currentCriteria,
+					rebuiltLog: '',
+					remainingCriteria,
+					remainingDamagedLog: entry.log,
+				},
+				new Map(),
+			);
 		})
-		.tap((a) => {
-			console.log(a);
-		})
-		.map((spring) => calculateVariations(spring.log, spring.criteria))
-
 		.sum();
 
-await task(p2, packageJson.aoc); // 7118 ~0ms
+await task(p2, packageJson.aoc); // 7030194981795 ~0ms
diff --git a/solutions/typescript/2023/12/src/parse.ts b/solutions/typescript/2023/12/src/parse.ts
@@ -0,0 +1,25 @@
+export interface SpringLog {
+	/**
+	 * `?` unknown
+	 * `.` operational
+	 * `#` damaged
+	 */
+	log: string;
+	criteria: number[];
+	criteriaRegExp: RegExp;
+}
+
+export const criteriaToRegExp = (criteria: number[]): RegExp =>
+	new RegExp('^\\.*' + criteria.map((brokenCount) => `#{${brokenCount}}`).join('\\.+') + '\\.*$');
+
+export const parse = (input: string): SpringLog[] => {
+	return input.lines(false).map<SpringLog>((line) => {
+		const [log, critRaw] = line.splitIntoStringPair(' ');
+		const crit = critRaw.splitToInt({ delimiter: /,/ });
+		return {
+			log,
+			criteria: crit,
+			criteriaRegExp: criteriaToRegExp(crit),
+		};
+	});
+};