Crawler Log Folder

Problem Description

You are given a list of strings logs where logs[i] represents a change folder operation performed by a user in a file system. Each operation can either move to the parent folder, remain in the same folder, or move to a child folder. The file system starts in the main folder, and your task is to determine the minimum number of operations needed to return to the main folder after executing all operations in logs.

Key Insights

• The operation "../" moves to the parent folder unless already in the main folder.
• The operation "./" keeps the current folder unchanged.
• The operation "x/" moves to a child folder named x, which always exists.
• To return to the main folder, only the "../" operations are necessary, while other operations do not affect the current depth.

Space and Time Complexity

Time Complexity: O(n) - where n is the number of logs, since we process each log exactly once.

Space Complexity: O(1) - no additional space is required that scales with input size.

Solution

To solve this problem, we can maintain a counter to track the depth of the current folder. We iterate through each log operation:

• For "../", we decrease the depth by 1, ensuring it doesn't go below zero.
• For "./", we do nothing as it does not change the depth.
• For "x/", we increase the depth by 1 since we are moving into a child folder.

At the end, the value of the depth counter will give us the number of "../" operations needed to return to the main folder, which is simply the depth itself.

Code Solutions