refactor(2025/day/2): RangeSet is overkill

For part 1, checking against the raw overlapping ranges is nearly just as fast and uses less memory.

For part 2, other RangeSet operations are not needed, only the initial merging which can be done more efficiently inline without using the data structure.

Author: mfulton26

2025/day/5/ingredients.ts

@@ -1,10 +1,8 @@
-import Range from "@lib/Range.ts";
-
-export function parseIngredientsDatabase(text: string) {
+export function parseDatabase(text: string) {
   const [top, bottom] = text.split("\n\n");
   const freshIdRanges = top.split("\n").map((text: string) => {
     const [start, end] = text.split("-").map(Number);
-    return new Range(start, end + 1);
+    return { start, end };
   });
   const availableIds = bottom.split("\n").map(Number);
   return { freshIdRanges, availableIds };

2025/day/5/part/1/solve.ts

@@ -1,12 +1,9 @@
-import RangeSet from "@lib/RangeSet.ts";
-import { parseIngredientsDatabase } from "../../ingredients.ts";
+import { parseDatabase } from "../../ingredients.ts";
 
 export default function solve(input: string) {
-  const { freshIdRanges, availableIds } = parseIngredientsDatabase(input);
-  const rangeSet = new RangeSet(freshIdRanges);
-  let freshCount = 0;
-  for (const availableId of availableIds) {
-    if (rangeSet.has(availableId)) freshCount++;
-  }
+  const { freshIdRanges, availableIds } = parseDatabase(input);
+  const { length: freshCount } = availableIds.filter((id) =>
+    freshIdRanges.some(({ start, end }) => id >= start && id <= end)
+  );
   return freshCount;
 }

2025/day/5/part/2/solve.ts

@@ -1,7 +1,16 @@
-import RangeSet from "@lib/RangeSet.ts";
-import { parseIngredientsDatabase } from "../../ingredients.ts";
+import { parseDatabase } from "../../ingredients.ts";
 
 export default function solve(input: string) {
-  const { freshIdRanges } = parseIngredientsDatabase(input);
-  return new RangeSet(freshIdRanges).size;
+  const { freshIdRanges } = parseDatabase(input);
+  freshIdRanges.sort((a, b) => a.start - b.start);
+  const merged: typeof freshIdRanges = [];
+  for (const { start, end } of freshIdRanges) {
+    const prevRange = merged.at(-1);
+    if (prevRange && start <= prevRange.end + 1) {
+      prevRange.end = Math.max(prevRange.end, end);
+    } else {
+      merged.push({ start, end });
+    }
+  }
+  return merged.reduce((sum, { start, end }) => sum + (end - start + 1), 0);
 }