From 205086e7dde92eac1fae22fb695b08640f01f66d Mon Sep 17 00:00:00 2001
From: wieerwill <robert.jeutter@gmx.de>
Date: Wed, 20 Dec 2023 18:04:16 +0100
Subject: [PATCH] solved Day19 in TS

---
 Day19/ts/solution.ts | 91 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 Day19/ts/solution.ts

diff --git a/Day19/ts/solution.ts b/Day19/ts/solution.ts
new file mode 100644
index 0000000..909a58b
--- /dev/null
+++ b/Day19/ts/solution.ts
@@ -0,0 +1,91 @@
+import * as fs from 'fs';
+
+type Range = [number, number];
+type WorkflowRule = [string, string, number, string];
+type WorkflowRules = WorkflowRule[];
+type Workflows = { [key: string]: [WorkflowRules, string] };
+
+function parseInput(filePath: string): Workflows {
+    const lines = fs.readFileSync(filePath, 'utf-8').split('\n').filter(line => line);
+    let workflows: Workflows = {};
+    let currentWorkflow: string[] = [];
+
+    for (const line of lines) {
+        if (!line.startsWith('{') && currentWorkflow.length > 0) {
+            processWorkflow(currentWorkflow);
+            currentWorkflow = [];
+        }
+        currentWorkflow.push(line);
+    }
+    if (currentWorkflow.length > 0) {
+        processWorkflow(currentWorkflow);
+    }
+
+    function processWorkflow(workflowLines: string[]) {
+        const [name, rulesStr] = workflowLines[0].split('{');
+        const rules = rulesStr.slice(0, -1).split(',');
+        workflows[name] = [[], rules.pop() as string];
+        for (const rule of rules) {
+            const [condition, target] = rule.split(':');
+            const [key, comparison, ...value] = Array.from(condition);
+            workflows[name][0].push([key, comparison, parseInt(value.join('')), target]);
+        }
+    }
+
+    return workflows;
+}
+
+function countRanges(workflows: Workflows, ranges: { [key: string]: Range }, name = 'in'): number {
+    if (name === 'R') return 0;
+    if (name === 'A') return Object.values(ranges).reduce((acc, [start, stop]) => acc * (stop - start + 1), 1);
+
+    const [rules, fallback] = workflows[name];
+    let total = 0;
+
+    for (const [key, comparison, value, target] of rules) {
+        const [start, stop] = ranges[key];
+        let tRange: Range, fRange: Range;
+
+        if (comparison === '<') {
+            tRange = [start, value - 1];
+            fRange = [value, stop];
+        } else {
+            tRange = [value + 1, stop];
+            fRange = [start, value];
+        }
+
+        if (tRange[0] <= tRange[1]) {
+            total += countRanges(workflows, { ...ranges, [key]: tRange }, target);
+        }
+        if (fRange[0] <= fRange[1]) {
+            ranges[key] = fRange;
+        } else {
+            break;
+        }
+    }
+    return total + countRanges(workflows, ranges, fallback);
+}
+
+function testAlgorithm(testFile: string, expected: number) {
+    const workflows = parseInput(testFile);
+    const result = countRanges(workflows, { 'x': [1, 4000], 'm': [1, 4000], 'a': [1, 4000], 's': [1, 4000] });
+    console.assert(result === expected, `Test failed: expected ${expected}, got ${result}`);
+    console.log('Test passed successfully.');
+}
+
+function main() {
+    try {
+        console.log('Running test...');
+        testAlgorithm('../test.txt', 167409079868000);
+
+        console.log('Test passed. Running on actual input...');
+        const workflows = parseInput('../input.txt');
+        const result = countRanges(workflows, { 'x': [1, 4000], 'm': [1, 4000], 'a': [1, 4000], 's': [1, 4000] });
+        console.log(`Result for the puzzle input: ${result}`);
+    } catch (error) {
+        console.error(`Error: ${error}`);
+        process.exit(1);
+    }
+}
+
+main();