0388-longest-absolute-file-path.js

/**
 * 388. Longest Absolute File Path
 * https://leetcode.com/problems/longest-absolute-file-path/
 * Difficulty: Medium
 *
 * Suppose we have a file system that stores both files and directories. An example of one system
 * is represented in the following picture:
 *
 * Here, we have dir as the only directory in the root. dir contains two subdirectories, subdir1
 * and subdir2. subdir1 contains a file file1.ext and subdirectory subsubdir1. subdir2 contains
 * a subdirectory subsubdir2, which contains a file file2.ext.
 * In text form, it looks like this (with ⟶ representing the tab character):
 *
 * dir
 * ⟶ subdir1
 * ⟶ ⟶ file1.ext
 * ⟶ ⟶ subsubdir1
 * ⟶ subdir2
 * ⟶ ⟶ subsubdir2
 * ⟶ ⟶ ⟶ file2.ext
 *
 * If we were to write this representation in code, it will look like this:
 * "dir\n\tsubdir1\n\t\tfile1.ext\n\t\tsubsubdir1\n\tsubdir2\n\t\tsubsubdir2\n\t\t\tfile2.ext".
 * Note that the '\n' and '\t' are the new-line and tab characters.
 *
 * Every file and directory has a unique absolute path in the file system, which is the order of
 * directories that must be opened to reach the file/directory itself, all concatenated by '/'s.
 * Using the above example, the absolute path to file2.ext is "dir/subdir2/subsubdir2/file2.ext".
 * Each directory name consists of letters, digits, and/or spaces. Each file name is of the form
 * name.extension, where name and extension consist of letters, digits, and/or spaces.
 *
 * Given a string input representing the file system in the explained format, return the length of
 * the longest absolute path to a file in the abstracted file system. If there is no file in the
 * system, return 0.
 *
 * Note that the testcases are generated such that the file system is valid and no file or directory
 * name has length 0.
 */

/**
 * @param {string} input
 * @return {number}
 */
var lengthLongestPath = function(input) {
  const stack = [0];
  let result = 0;

  for (const line of input.split('\n')) {
    const level = line.lastIndexOf('\t') + 1;
    while (stack.length > level + 1) stack.pop();
    stack.push(stack.at(-1) + line.length - level + 1);
    if (line.includes('.')) {
      result = Math.max(result, stack.at(-1) - 1);
    }
  }

  return result;
};