solutions/1598-crawler-log-folder.js

/**
 * 1598. Crawler Log Folder
 * https://leetcode.com/problems/crawler-log-folder/
 * Difficulty: Easy
 *
 * The Leetcode file system keeps a log each time some user performs
 * a change folder operation.
 *
 * The operations are described below:
 *
 * - `"../"` : Move to the parent folder of the current folder. (If
 *   you are already in the main folder, remain in the same folder).
 * - `"./"` : Remain in the same folder.
 * - `"x/"` : Move to the child folder named x (This folder is
 *   guaranteed to always exist).
 *
 * You are given a list of strings logs where logs[i] is the operation
 * performed by the user at the ith step.
 *
 * The file system starts in the main folder, then the operations in
 * logs are performed.
 *
 * Return the minimum number of operations needed to go back to the
 * main folder after the change folder operations.
 */

/**
 * @param {string[]} logs
 * @return {number}
 */
var minOperations = function(logs) {
  return logs.reduce((depth, log) =>
    Math.max(0, depth + (log === '../' ? -1 : log === './' ? 0 : 1)), 0
  );
};