first commit

day02/input.txt

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+3335355312-3335478020,62597156-62638027,94888325-95016472,4653-6357,54-79,1-19,314-423,472-650,217886-298699,58843645-58909745,2799-3721,150748-178674,9084373-9176707,1744-2691,17039821-17193560,2140045-2264792,743-1030,6666577818-6666739950,22946-32222,58933-81008,714665437-714803123,9972438-10023331,120068-142180,101-120,726684-913526,7575737649-7575766026,8200-11903,81-96,540949-687222,35704-54213,991404-1009392,335082-425865,196-268,3278941-3383621,915593-991111,32-47,431725-452205

day02/js/day02a.js

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+import { promises as fsp } from "node:fs";
+
+async function asyncReadFile(filename) {
+    try {
+        const contents = await fsp.readFile(filename, "utf-8");
+
+        return contents.trim();
+    } catch (err) {
+        console.error(err);
+    }
+}
+
+/*
+const dataToParse =
+    "11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,446443-446449,38593856-38593862,565653-565659,824824821-824824827,2121212118-2121212124";
+*/
+
+const dataToParse = await asyncReadFile("../input.txt");
+
+const isDuplicate = (val = "") => {
+    const strVal = `${val}`,
+        strLen = strVal.length;
+    if (!strLen || strLen % 2 === 1) return false;
+
+    return strVal.substring(0, strLen / 2) === strVal.substring(strLen / 2);
+};
+
+const ranges = dataToParse.split(",");
+let total = 0;
+
+ranges.forEach((range) => {
+    console.log(`> running range ${range}`);
+    const [start, end] = range.split("-"),
+        last = end * 1;
+    let curr = start * 1;
+    while (curr <= last) {
+        if (isDuplicate(curr)) {
+            total += curr;
+            console.log(`>> found duplicate: ${curr} / ${total}`);
+        }
+        curr++;
+    }
+});
+
+console.log(`> FINAL: ${total}`);

day02/js/day02b.js

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+import { promises as fsp } from "node:fs";
+
+async function asyncReadFile(filename) {
+    try {
+        const contents = await fsp.readFile(filename, "utf-8");
+
+        return contents.trim();
+    } catch (err) {
+        console.error(err);
+    }
+}
+
+/*
+const dataToParse =
+    "11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,446443-446449,38593856-38593862,565653-565659,824824821-824824827,2121212118-2121212124";
+*/
+
+const dataToParse = await asyncReadFile("../input.txt");
+
+const isDuplicateOld = (val = "") => {
+    const strVal = `${val}`,
+        strLen = strVal.length;
+    if (!strLen || strLen % 2 === 1) return false;
+
+    return strVal.substring(0, strLen / 2) === strVal.substring(strLen / 2);
+};
+
+const duplicateRE = /^(\d+)\1+$/;
+const isDuplicate = (val = "") => {
+    // new process - runa  regex that looks for repeats from start to end
+    const strVal = `${val}`,
+        strLen = strVal.length;
+    if (!strLen) return false;
+
+    const matches = strVal.match(duplicateRE);
+
+    if (matches === null) return false;
+
+    return matches.length >= 1 && matches[0] === strVal;
+};
+
+const ranges = dataToParse.split(",");
+let total = 0;
+
+ranges.forEach((range) => {
+    console.log(`> running range ${range}`);
+    const [start, end] = range.split("-"),
+        last = end * 1;
+    let curr = start * 1;
+    while (curr <= last) {
+        if (isDuplicate(curr)) {
+            total += curr;
+            console.log(`>> found duplicate: ${curr} / ${total}`);
+        }
+        curr++;
+    }
+});
+
+console.log(`> FINAL: ${total}`);

day02/notes.md

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+## Day 2: Gift Shop
+
+This got a bit frustrating with the regex in the second part.
+
+It only took about 30 minutes to solve first part, but my answer involved literally splitting strings, so it didn't work for arbitrary matches and had to be replaced by a regex solution. After struggling with the regex for another 30 minutes, I put it away until the next day, when a 5-minute web search lead me to the fix for my bad regex.
+
+### JS Solutions
+
+```
+cd js
+node day01a.js
+node day01b.js
+```