1598. Crawler Log Folder

Time: O(n)

Space: O(1)

Intuition

Count operations on a file system. Only valid operations increment the counter: mkdir creates a new folder, rmdir removes empty folder. Others (cd, ls) don't count.

Algorithm

1For each log entry: increment count. But "cd .." and "ls" don't count, nor does "cd x" if x exists in current directory.
2Wait: problem counts minimum operations to return to main folder from cd operations. Use depth tracking.

Common Pitfalls

•Each "cd x" where x!=".." increases depth by 1. "../" decreases by 1 (floor 0). "./" stays. Return final depth.

1598.cs

// Approach: Simulate directory depth: '../' decrements, './' stays, otherwise increment; clamp at 0.
// Time: O(n) Space: O(1)

public class Solution
{
    public int MinOperations(string[] logs)
    {
        int ops = 0;

        foreach (string log in logs)
        {
            if (log == "./")
                continue;

            if (log == "../")
            {
                if (ops > 0)
                    ops--;
            }
            else
                ops++;
        }

        return ops;
    }
}

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