71. Simplify Path.md

71. Simplify Path

• Difficulty: Medium.
• Related Topics: String, Stack.
• Similar Questions: .

Problem

Given an absolute path for a file (Unix-style), simplify it.

For example, path = "/home/", => "/home" path = "/a/./b/../../c/", => "/c"

Corner Cases:

Did you consider the case where path = "/../"? In this case, you should return "/".

Another corner case is the path might contain multiple slashes '/' together, such as "/home//foo/". In this case, you should ignore redundant slashes and return "/home/foo".

Solution

/**
 * @param {string} path
 * @return {string}
 */
var simplifyPath = function(path) {
  var arr = path.split('/');
  var stack = [];
  var len = arr.length;
  var item = '';
  for (var i = 0; i < len; i++) {
    item = arr[i];
    if (item === '' || item === '.') continue;
    if (item === '..') {
      stack.pop();
    } else {
      stack.push(item);
    }
  }
  return '/' + stack.join('/');
};

Explain:

栈。

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).