Crawler Log Folder — LeetCode 1598 Python Solution

The problem

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.

Example

Input

logs = ["d1/","d2/","../","d21/","./"]

Output

2

Explanation

Use this change folder operation "../" 2 times and go back to the main folder.

Python solution

class Solution:
    def minOperations(self, logs: List[str]) -> int:
        ans = 0
        for v in logs:
            if v == "../":
                ans = max(0, ans - 1)
            elif v[0] != ".":
                ans += 1
        return ans

Complexity

Pattern: Stack

When the most recent unresolved thing is the one that matters, use a stack. LeetCode 1598. Crawler Log Folder is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Stack.

The stack guide has the Python template for the pattern and the 194 LeetCode problems that use it.

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