> For the complete documentation index, see [llms.txt](https://mayanktyagi3111.gitbook.io/interview-prep/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mayanktyagi3111.gitbook.io/interview-prep/stacks-and-queues/simplify-path.md).

# Simplify Path

Given an **absolute path** for a file (Unix-style), simplify it. Or in other words, convert it to the **canonical path**.

In a UNIX-style file system, a period `.` refers to the current directory. Furthermore, a double period `..` moves the directory up a level.

Note that the returned canonical path must always begin with a slash `/`, and there must be only a single slash `/` between two directory names. The last directory name (if it exists) **must not** end with a trailing `/`. Also, the canonical path must be the **shortest** string representing the absolute path.

**Example 1:**

```
Input: "/home/"
Output: "/home"
Explanation: Note that there is no trailing slash after the last directory name.
```

**Example 2:**

```
Input: "/../"
Output: "/"
Explanation: Going one level up from the root directory is a no-op, as the root level is the highest level you can go.
```

**Example 3:**

```
Input: "/home//foo/"
Output: "/home/foo"
Explanation: In the canonical path, multiple consecutive slashes are replaced by a single one.
```

**Example 4:**

```
Input: "/a/./b/../../c/"
Output: "/c"
```

**Example 5:**

```
Input: "/a/../../b/../c//.//"
Output: "/c"
```

**Example 6:**

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

```java
class Solution {
    public String simplifyPath(String path) {
        Stack<String> stack = new Stack<>();
        Set<String> skip = new HashSet<>(Arrays.asList("..", ".", ""));
        for (String dir : path.split("/")) {
            if (dir.equals("..") && !stack.isEmpty())
                stack.pop();
            else if (!skip.contains(dir))
                stack.push(dir);
        }
        String res = "";
        for (String dir : stack){
            res = res + "/" + dir;
        }
        return res.isEmpty() ? "/" : res;
    }
}
```