> 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/linked-list/design-browser-history.md).

# Design Browser History

You have a **browser** of one tab where you start on the `homepage` and you can visit another `url`, get back in the history number of `steps` or move forward in the history number of `steps`.

Implement the `BrowserHistory` class:

* `BrowserHistory(string homepage)` Initializes the object with the `homepage` of the browser.
* `void visit(string url)` visits `url` from the current page. It clears up all the forward history.
* `string back(int steps)` Move `steps` back in history. If you can only return `x` steps in the history and `steps > x`, you will return only `x` steps. Return the current `url` after moving back in history **at most** `steps`.
* `string forward(int steps)` Move `steps` forward in history. If you can only forward `x` steps in the history and `steps > x`, you will forward only `x` steps. Return the current `url` after forwarding in history **at most** `steps`.

**Example:**

```
Input:
["BrowserHistory","visit","visit","visit","back","back","forward","visit","forward","back","back"]
[["leetcode.com"],["google.com"],["facebook.com"],["youtube.com"],[1],[1],[1],["linkedin.com"],[2],[2],[7]]
Output:
[null,null,null,null,"facebook.com","google.com","facebook.com",null,"linkedin.com","google.com","leetcode.com"]

Explanation:
BrowserHistory browserHistory = new BrowserHistory("leetcode.com");
browserHistory.visit("google.com");       // You are in "leetcode.com". Visit "google.com"
browserHistory.visit("facebook.com");     // You are in "google.com". Visit "facebook.com"
browserHistory.visit("youtube.com");      // You are in "facebook.com". Visit "youtube.com"
browserHistory.back(1);                   // You are in "youtube.com", move back to "facebook.com" return "facebook.com"
browserHistory.back(1);                   // You are in "facebook.com", move back to "google.com" return "google.com"
browserHistory.forward(1);                // You are in "google.com", move forward to "facebook.com" return "facebook.com"
browserHistory.visit("linkedin.com");     // You are in "facebook.com". Visit "linkedin.com"
browserHistory.forward(2);                // You are in "linkedin.com", you cannot move forward any steps.
browserHistory.back(2);                   // You are in "linkedin.com", move back two steps to "facebook.com" then to "google.com". return "google.com"
browserHistory.back(7);                   // You are in "google.com", you can move back only one step to "leetcode.com". return "leetcode.com"
```

**Constraints:**

* `1 <= homepage.length <= 20`
* `1 <= url.length <= 20`
* `1 <= steps <= 100`
* `homepage` and `url` consist of  '.' or lower case English letters.
* At most `5000` calls will be made to `visit`, `back`, and `forward`.

```java
class BrowserHistory {
    LinkedList<String> list;
    int pointer, len;

    public BrowserHistory(String homepage) {
        list = new LinkedList<>();
        list.add(homepage);
        pointer = 0;
        len = 1;
    }

    public void visit(String url) {
        pointer++;
        list.add(pointer, url);
        len = pointer + 1;
    }

    public String back(int steps) {
        while (pointer > 0 && steps-- > 0) {
            pointer--;
        }
        return list.get(pointer);
    }

    public String forward(int steps) {
        while (pointer < len - 1 && steps-- > 0)
            pointer++;
        return list.get(pointer);
    }
}
```


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