2024 Day 05

2024/d05/index.ts

@@ -0,0 +1,89 @@
+import { readFileSync } from 'node:fs'
+
+import { runExamples, runSolution } from '@magiczne/advent-of-code-ts-core/aoc'
+
+type Input = { rules: ReadonlyArray<[number, number]>; updates: ReadonlyArray<ReadonlyArray<number>> }
+
+const isUpdateValid = (rules: ReadonlyArray<[number, number]>, update: ReadonlyArray<number>): boolean => {
+  return rules
+    .filter(rule => rule.every(ruleItem => update.includes(ruleItem)))
+    .every(rule => update.indexOf(rule[0]) < update.indexOf(rule[1]))
+}
+
+const getNotFullfiledRules = (
+  rules: ReadonlyArray<[number, number]>,
+  update: ReadonlyArray<number>,
+): ReadonlyArray<[number, number]> => {
+  return rules
+    .filter(rule => rule.every(ruleItem => update.includes(ruleItem)))
+    .filter(rule => update.indexOf(rule[0]) > update.indexOf(rule[1]))
+}
+
+const part1 = (data: Input): number => {
+  return data.updates
+    .filter(update => isUpdateValid(data.rules, update))
+    .reduce((acc, update) => acc + update[Math.floor(update.length / 2)], 0)
+
+  return 0
+}
+
+const part2 = (data: Input): number => {
+  const reorder = (
+    notFullfiledRules: ReadonlyArray<[number, number]>,
+    update: ReadonlyArray<number>,
+  ): ReadonlyArray<number> => {
+    if (notFullfiledRules.length === 0) {
+      return update
+    }
+
+    const firstIndex = update.findIndex(item => item === notFullfiledRules[0][0])
+    const secondIndex = update.findIndex(item => item === notFullfiledRules[0][1])
+    const mudatedUpdate = update.toSpliced(firstIndex, 1).toSpliced(secondIndex, 0, update[firstIndex])
+
+    return reorder(getNotFullfiledRules(data.rules, mudatedUpdate), mudatedUpdate)
+  }
+
+  return data.updates
+    .map(update => {
+      const notFulfilledRules = getNotFullfiledRules(data.rules, update)
+
+      // Removing lines that are correct from beginning
+      if (notFulfilledRules.length === 0) {
+        return null
+      }
+
+      return reorder(notFulfilledRules, update)
+    })
+    .filter(item => item !== null)
+    .reduce((acc, update) => {
+      return acc + update[Math.floor(update.length / 2)]
+    }, 0)
+}
+
+const reader = (file: string): Input => {
+  const [rawRules, rawUpdates] = readFileSync(file, 'utf-8').trim().split('\n\n')
+
+  return {
+    rules: rawRules
+      .trim()
+      .split('\n')
+      .map(rule => {
+        return rule
+          .trim()
+          .split('|')
+          .map(n => parseInt(n, 10)) as [number, number]
+      }),
+    updates: rawUpdates
+      .trim()
+      .split('\n')
+      .map(update => {
+        return update
+          .trim()
+          .split(',')
+          .map(n => parseInt(n, 10))
+      }),
+  }
+}
+
+runExamples(2024, '05', reader, part1, part2)
+runSolution(2024, '05', reader, part1, part2)