part-2.ts

// Heavily inspired from JPBM135's result:
// https://github.com/JPBM135/advent-of-coding-2022/blob/main/day-07/index.ts

import { getInput } from "../../../src/get-input.ts";

const input = getInput(2022, 7);

const lines = input.split("\n");

const dirSizes = new Map<string, number>();
const currentDir: string[] = [];

for (const line of lines) {
  const split = line.split(" ");
  if (line.startsWith("$ cd")) {
    const dirName = split[2];
    if (dirName === "..") {
      currentDir.pop();
    } else {
      currentDir.push(dirName);
    }
    continue;
  } else {
    if (split[0] === "dir" || line.startsWith("$")) continue;
    for (let count = 0; count < currentDir.length + 1; count++) {
      const filePath = `/${currentDir.slice(0, count).join("/")}`;
      const fileSize = parseInt(line) + (dirSizes.get(filePath) ?? 0);
      dirSizes.set(filePath, fileSize);
    }
  }
}

const dirArr = [...dirSizes.entries()];

const totalSize = 70_000_000;
const upgradeSize = 30_000_000;
const usedSize = dirSizes.get("/")!;
const freeSize = totalSize - usedSize;
const sizeNeeded = upgradeSize - freeSize;

const deletionPossibilities = dirArr.filter((size) => size[1] >= sizeNeeded).sort((a, b) => a[1] - b[1]);
console.log(deletionPossibilities[0][1]);