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#71 - Simplify Path

Problem Description

You are given an absolute path for a Unix-style file system, which always begins with a slash '/'. Your task is to transform this absolute path into its simplified canonical path.

The rules of a Unix-style file system are as follows:

  • A single period '.' represents the current directory.
  • A double period '..' represents the previous/parent directory.
  • Multiple consecutive slashes such as '//' and '///' are treated as a single slash '/'.
  • Any sequence of periods that does not match the rules above should be treated as a valid directory or file name. For example, '...' and '....' are valid directory or file names.

The simplified canonical path should follow these rules:

  • The path must start with a single slash '/'.
  • Directories within the path must be separated by exactly one slash '/'.
  • The path must not end with a slash '/', unless it is the root directory.
  • The path must not have any single or double periods ('.' and '..') used to denote current or parent directories.

Return the simplified canonical path.

Solution

/**
 * @param {string} path
 * @return {string}
 */
var simplifyPath = function(path) {
  const stack = [];
  for (const segment of path.split('/')) {
    if (segment === '.' || segment === '') continue;
    if (segment === '..') stack.pop();
    else stack.push(segment);
  }
  return `/${stack.join('/')}`;
};