05/2025

Author: breadadams

2024/05/index.ts

@@ -0,0 +1,111 @@
+import { getPuzzle } from "../../utils";
+
+const puzzleInput = getPuzzle(__dirname).trim();
+
+let [_orderingRules, _pagesToProduce] = puzzleInput.split("\n\n");
+
+const orderingRules = _orderingRules
+  .split("\n")
+  .map((row) => row.split("|").map((num) => parseInt(num)));
+
+const pagesToProduce = _pagesToProduce
+  .split("\n")
+  .map((row) => row.split(",").map((num) => parseInt(num)));
+
+const arePagesValid = (row: number[]) => {
+  let isValid = true;
+
+  for (let j = 0; j < row.length; j++) {
+    const page = row[j];
+    const relevantRules = orderingRules.filter((rule) => rule.includes(page));
+
+    if (!relevantRules.length) {
+      break;
+    }
+
+    for (let k = 0; k < row.length; k++) {
+      const otherPage = row[k];
+      if (k === j) {
+        continue;
+      }
+
+      const rule = relevantRules.find((rule) => rule.includes(otherPage));
+
+      if (
+        (k < j && rule.indexOf(otherPage) === 1) ||
+        (k > j && rule.indexOf(otherPage) === 0)
+      ) {
+        isValid = false;
+        break;
+      }
+    }
+
+    if (!isValid) {
+      break;
+    }
+  }
+
+  return isValid;
+};
+
+// Part 1
+(() => {
+  console.time("part 1");
+
+  let total = 0;
+
+  for (let i = 0; i < pagesToProduce.length; i++) {
+    const row = pagesToProduce[i];
+    let isValid = arePagesValid(row);
+
+    if (isValid) {
+      total += row[Math.floor(row.length / 2)];
+    }
+  }
+
+  console.log("total part 1 ::", total);
+  console.timeEnd("part 1");
+})();
+
+// Part 2
+(() => {
+  console.time("part 2");
+
+  let total = 0;
+  let invalidUpdates: typeof orderingRules = [];
+
+  for (let i = 0; i < pagesToProduce.length; i++) {
+    const row = pagesToProduce[i];
+    let isValid = arePagesValid(row);
+
+    if (!isValid) {
+      invalidUpdates.push(row);
+    }
+  }
+
+  for (let i = 0; i < invalidUpdates.length; i++) {
+    const row = [...invalidUpdates[i]];
+
+    row.sort((a, b) => {
+      const rule = orderingRules.find(
+        (rule) =>
+          (rule[0] === a && rule[1] === b) || (rule[0] === b && rule[1] === a)
+      );
+
+      if (rule[0] === a) {
+        return -1;
+      }
+
+      if (rule[1] === a) {
+        return 1;
+      }
+
+      return 0;
+    });
+
+    total += row[Math.floor(row.length / 2)];
+  }
+
+  console.log("total part 2 ::", total);
+  console.timeEnd("part 2");
+})();

README.md

@@ -6,6 +6,7 @@
 
 |                    Day                    | Part 1 | Part 2 |
 | :---------------------------------------: | :----: | :----: |
+| [05](https://adventofcode.com/2024/day/5) |   ✅   |   ✅   |
 | [04](https://adventofcode.com/2024/day/4) |   ✅   |   ✅   |
 | [03](https://adventofcode.com/2024/day/3) |   ✅   |   ✅   |
 | [02](https://adventofcode.com/2024/day/2) |   ✅   |   ✅   |