Crawler Log Folder

class Solution {
public:
    int minOperations(vector<string>& logs) {
        stack<string> pathStack;

        for (auto& log : logs) {
            if (log == "../") {
                if (!pathStack.empty()) {
                    pathStack.pop();
                }
            } else if (log != "./") {
                pathStack.push(log);
            }
        }

        return pathStack.size();
    }
};

The provided solution handles the problem of simulating a file system crawler's traversal through log folders, each represented by a string in a vector. Written in C++, the solution makes use of a stack to track the directory level the crawler is at after processing all operations listed in the logs.

The function, minOperations, accepts a vector of strings wherein each log entry can be:

• "../" indicating moving back to the parent directory,
• "./" representing the current directory,
• or a folder name indicating moving into that folder.

The core logic involves iterating through each log entry and using the stack data structure to either push a new log folder, pop the stack when moving back, or do nothing when staying in the current folder. Here's a clear stepwise breakdown of the operations:

1. Initialize a stack<string> to hold the path history.

2. Iterate over each log in the input vector:

   • If the log is "../" and the stack is not empty, pop the top entry from the stack.
   • If the log is a directory name (i.e., not "./" or "../"), push it onto the stack.

3. At the end of the loop, return the size of the stack. This represents the minimum number of operations needed to return to the main folder after processing all the log entries.

This approach efficiently leverages the stack's LIFO (Last In, First Out) property to backtrack correctly through the directories and avoids any unnecessary operations for entries referring to the current directory.

class Solution {

    public int findDepth(String[] operations) {
        Stack<String> directoryStack = new Stack<>();

        for (String currentOperation : operations) {
            if (currentOperation.equals("../")) {
                if (!directoryStack.isEmpty()) {
                    directoryStack.pop();
                }
            } else if (!currentOperation.equals("./")) {
                directoryStack.push(currentOperation);
            }
        }

        return directoryStack.size();
    }
}

The problem "Crawler Log Folder" focuses on determining the minimum steps required to return to the root folder after performing several directory operations represented by strings. The solution uses Java and involves the following:

1. Define the Method: The findDepth method takes an array of strings operations as input, each string representing an operation on the folder structure.

2. Initialize a Stack: A Stack<String> named directoryStack is used to track the depth of the directory structure, pushing and popping directories based on the operations performed.

3. Process Each Operation:

   • Loop through each operation represented by the string array.
   • If the operation is "../" (move up one directory), pop the stack if it's not empty, effectively moving up one level.
   • If the operation is "./" (stay in the current directory), ignore this operation.
   • Any other operation (assumed to represent moving into a new directory), push this operation onto the stack.

4. Return Stack Size: After processing all operations, the size of the stack indicates the depth of the final directory level relative to the root.

By the end of this process, obtain the number of steps required to move from the root to the final directory location by returning the size of the directoryStack. This approach effectively handles all directory moves, correctly mimicking the file navigation.

class Solution:
    def calculateDepth(self, operations: List[str]) -> int:
        path_depth = []

        for operation in operations:
            if operation == "../":
                if path_depth:
                    path_depth.pop()
            elif operation != "./":
                path_depth.append(operation)
        
        return len(path_depth)

The solution for the "Crawler Log Folder" problem calculates the depth of a folder after executing a series of operations. The code is written in Python and utilizes a list to simulate the operations on the folder structure. Each operation in the list either navigates to a parent directory, remains in the current directory, or moves into a subdirectory. Here's how the solution works:

• Initialize an empty list path_depth to represent the stack of operations.
• Iterate through each operation in the input list operations.
  • If the operation is "../", check if path_depth is not empty to pop the last operation (move to the parent directory).
  • If the operation is not "./", append it to path_depth as it indicates moving to a new subdirectory.
• After processing all operations, the depth of the folder is given by the length of path_depth, which is returned as the result.

This approach ensures that any operation leading outside the root directory is ignored, and keeps track of the depth purely based on valid navigational operations. The method is efficient, utilizing list operations to dynamically simulate the folder navigation.