> ## Documentation Index
> Fetch the complete documentation index at: https://leetcode-py.wisl.dev/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> leetcode-py is a Python LeetCode practice environment generator with one CLI: lcpy. It is not a service or platform.
> Each problem is a directory under leetcode/ with README.md, solution.py, test_solution.py, helpers.py, and playground.ipynb. lcpy gen creates them from JSON templates bundled with the package.
> Examples are backed by tests; copy them verbatim.

# Simplify Path Python Solution with Tests

> Tested Python solution for LeetCode 71 with 18 pytest cases. Generate a practice environment with lcpy.

LeetCode 71, Medium. Topics: String, Stack. [View on LeetCode](https://leetcode.com/problems/simplify-path/description/).

Generate this problem as a practice environment: tested reference solution, 18 [parametrized pytest cases](/practice/testing), and a playground notebook:

```bash theme={"theme":{"light":"github-light","dark":"github-dark"}}
lcpy gen -n 71   # by problem number
lcpy gen -s simplify_path   # by problem name
```

## Problem

You are given an *absolute* path for a Unix-style file system, which always begins with a slash `/`. Your task is to transform this absolute path into its **simplified canonical path**.

The *rules* of a Unix-style file system are as follows:

* A single period `'.'` represents the current directory.
* A double period `'..'` represents the previous/parent directory.
* Multiple consecutive slashes such as `'//'` and `'///'` are treated as a single slash `'/'`.
* Any sequence of periods that does **not match** the rules above should be treated as a **valid directory or file name**. For example, `'...'` and `'....'` are valid directory or file names.

The simplified canonical path should follow these *rules*:

* The path must start with a single slash `'/'`.
* Directories within the path must be separated by exactly one slash `'/'`.
* The path must not end with a slash `'/'`, unless it is the root directory.
* The path must not have any single or double periods (`'.'` and `'..'`) used to denote current or parent directories.

Return the **simplified canonical path**.

### Examples

```
Input: path = "/home/"
Output: "/home"
```

**Explanation:**

The trailing slash should be removed.

```
Input: path = "/home//foo/"
Output: "/home/foo"
```

**Explanation:**

Multiple consecutive slashes are replaced by a single one.

```
Input: path = "/home/user/Documents/../Pictures"
Output: "/home/user/Pictures"
```

**Explanation:**

A double period `".."` refers to the directory up a level (the parent directory).

```
Input: path = "/../"
Output: "/"
```

**Explanation:**

Going one level up from the root directory is not possible.

```
Input: path = "/.../a/../b/c/../d/./"
Output: "/.../b/d"
```

**Explanation:**

`"..."` is a valid name for a directory in this problem.

### Constraints

* 1 \<= path.length \<= 3000
* `path` consists of English letters, digits, period `'.'`, slash `'/'` or `'_'`.
* `path` is a valid absolute Unix path.

## Solution

Reference implementation from [solution.py on GitHub](https://github.com/wislertt/leetcode-py/blob/main/leetcode/simplify_path/solution.py), full suite in [test\_solution.py](https://github.com/wislertt/leetcode-py/blob/main/leetcode/simplify_path/test_solution.py):

```python theme={"theme":{"light":"github-light","dark":"github-dark"}}
class Solution:
    # Time: O(n)
    # Space: O(n)
    def simplify_path(self, path: str) -> str:
        stack: list[str] = []

        for part in path.split("/"):
            if part == "" or part == ".":
                continue
            if part == "..":
                if stack:
                    stack.pop()
            else:
                stack.append(part)

        return "/" + "/".join(stack)
```

## Complexity

| Time | Space |
| ---- | ----- |
| O(n) | O(n)  |

## Tags

[NeetCode 250](/catalog/neetcode-250), [NeetCode All](/catalog/neetcode).