Web Browser History

Task

You are building a web browser. Implement a browser history that supports the following operations:

1. Visit URL: Visit the given URL and add it to the history list.
2. Move Back: Move back one URL, if any in the history list. Stay on current if none.
3. Move Forward: Move forward one URL, if any in the history list. Stay on current if none.

Class Definition

visit(url): Updates "current url" with the given url and load it into the browser. Maintains it in history list.

back(): Moves one step back in the browsing history and returns the URL, returns current url if none.

forward(): Moves one step forward in the browsing history and returns the URL.

Example Usage

Example 1

visit("google.com")
visit("amazon.com")
visit("youtube.com")
back() // Returns "amazon.com"
back() // Returns "google.com"
forward() // Returns "amazon.com"
visit("linkedin.com")
forward() // Returns "linkedin.com" (No forward history after visiting a new page)

Example 2

visit("leetcode.com")
back() // Returns "leetcode.com" (No previous page)
forward() // Returns "leetcode.com" (No forward history)

Example 3 (Edge Case - Empty History)

back() // Returns "empty"
forward() // Returns "empty"