day 6 complete!

day03/js/day03b.js

@@ -0,0 +1,62 @@
+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 findIndexOfHighestNumber = (arrayOfNumbers, start, end) => {
+    let highestIndex = start;
+    for (let i = start; i <= end; i++) {
+        if (arrayOfNumbers[i] > arrayOfNumbers[highestIndex]) highestIndex = i;
+    }
+    return highestIndex;
+};
+
+const findHighestOutput = (bank) => {
+    let arr = Array.from(bank);
+    let curr = Array(arr.length).fill("");
+    let foundNumbers = 0;
+    const desiredNumbers = 12;
+    let start = 0;
+
+    while (foundNumbers < desiredNumbers) {
+        const index = findIndexOfHighestNumber(
+            bank,
+            start,
+            arr.length - desiredNumbers + foundNumbers
+        );
+        curr[index] = arr[index];
+
+        // prep next run
+        foundNumbers++;
+        start = index + 1;
+    }
+    return Number.parseInt(curr.join(""), 10);
+};
+
+/*
+const dataToParse = `987654321111111
+811111111111119
+234234234234278
+818181911112111`;
+*/
+
+const dataToParse = await asyncReadFile("../input.txt");
+
+const banks = dataToParse.split("\n");
+let total = 0;
+
+banks.forEach((bank) => {
+    console.log(`Processing bank ${bank}`);
+    const output = findHighestOutput(bank);
+    console.log(`> found ${output}`);
+    total += output;
+});
+
+console.log(`Total: ${total}`);

day03/notes.md

@@ -6,9 +6,12 @@ But it was also brute force - literally stepping through each possible combinati
 
 ATM (11:30p Wed), I've got an algorithm that tries to create the highest value number by pulling out numbers in reverse numerical order, but it isn't _quite_ working. My current hope is to come at it fresh tomorrow when I also tackle puzzle 4.
 
+_UPDATE:_ Two days later, and I finally figured out the algorithm I needed to get the value. I thought I had it with an overcomplicated function that tried to count down from right to left, but in the end, the solution wound up being much simpler.
+
 ### JS Solutions
 
 ```
 cd js
 node day03a.js
+node day03b.js
 ```