> For the complete documentation index, see [llms.txt](https://anton-veselskyi.gitbook.io/codding-problems-solutions/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://anton-veselskyi.gitbook.io/codding-problems-solutions/codewars/6-kyu/linked-lists-length-count.md).

# Linked Lists - Length & Count

## [Linked Lists - Length & Count](https://www.codewars.com/kata/55beec7dd347078289000021)

Linked Lists - Length & Count

Implement Length() to count the number of nodes in a linked list.<br>

```javascript
length(null) => 0
length(1 -> 2 -> 3 -> null) => 3
```

```csharp
Node.Length(nullptr) => 0
Node.Length(1 -> 2 -> 3 -> nullptr) => 3
```

```cpp
length(null) => 0
length(1 -> 2 -> 3 -> null) => 3
```

Implement Count() to count the occurrences of an integer in a linked list.

```javascript
count(null, 1) => 0
count(1 -> 2 -> 3 -> null, 1) => 1
count(1 -> 1 -> 1 -> 2 -> 2 -> 2 -> 2 -> 3 -> 3 -> null, 2) => 4
```

```csharp
Node.Count(null, value => value == 1) => 0
Node.Count(1 -> 3 -> 5 -> 6, value => value % 2 != 0) => 3
```

```cpp
count(null, 1) => 0
count(1 -> 2 -> 3 -> nullptr, 1) => 1
count(1 -> 1 -> 1 -> 2 -> 2 -> 2 -> 2 -> 3 -> 3 -> nullptr, 2) => 4
```

I've decided to bundle these two functions within the same Kata since they are both very similar.

The `push()`/`Push()` and `buildOneTwoThree()`/`BuildOneTwoThree()` functions do not need to be redefined.

Related Kata in order of expected completion (increasing difficulty):\
&#x20;[Linked Lists - Push & BuildOneTwoThree](http://www.codewars.com/kata/linked-lists-push-and-buildonetwothree)\
&#x20;[Linked Lists - Length & Count](http://www.codewars.com/kata/linked-lists-length-and-count)\
&#x20;[Linked Lists - Get Nth Node](http://www.codewars.com/kata/linked-lists-get-nth-node)\
&#x20;[Linked Lists - Insert Nth Node](http://www.codewars.com/kata/linked-lists-insert-nth-node)\
&#x20;[Linked Lists - Sorted Insert](http://www.codewars.com/kata/linked-lists-sorted-insert)\
&#x20;[Linked Lists - Insert Sort](http://www.codewars.com/kata/linked-lists-insert-sort)\
&#x20;[Linked Lists - Append](http://www.codewars.com/kata/linked-lists-append)\
&#x20;[Linked Lists - Remove Duplicates](http://www.codewars.com/kata/linked-lists-remove-duplicates)\
&#x20;[Linked Lists - Move Node](http://www.codewars.com/kata/linked-lists-move-node)\
&#x20;[Linked Lists - Move Node In-place](http://www.codewars.com/kata/linked-lists-move-node-in-place)\
&#x20;[Linked Lists - Alternating Split](http://www.codewars.com/kata/linked-lists-alternating-split)\
&#x20;[Linked Lists - Front Back Split](http://www.codewars.com/kata/linked-lists-front-back-split)\
&#x20;[Linked Lists - Shuffle Merge](http://www.codewars.com/kata/linked-lists-shuffle-merge)\
&#x20;[Linked Lists - Sorted Merge](http://www.codewars.com/kata/linked-lists-sorted-merge)\
&#x20;[Linked Lists - Merge Sort](http://www.codewars.com/kata/linked-lists-merge-sort)\
&#x20;[Linked Lists - Sorted Intersect](http://www.codewars.com/kata/linked-lists-sorted-intersect)\
&#x20;[Linked Lists - Iterative Reverse](http://www.codewars.com/kata/linked-lists-iterative-reverse)\
&#x20;[Linked Lists - Recursive Reverse](http://www.codewars.com/kata/linked-lists-recursive-reverse)<br>

Inspired by Stanford Professor Nick Parlante's excellent [Linked List teachings.](http://cslibrary.stanford.edu/103/LinkedListBasics.pdf)

## Solutions

### 🧠 C++

```cpp
/* Node Definition
struct Node {
  Node * next;
  int data;
}
*/

int Length(Node *head)
{
  int counter = 0;
  for(;head!=nullptr;head=head->next)
    ++counter;
  return counter;
}

int Count(Node *head, int data)
{
  int counter = 0;
  for(;head!=nullptr;head=head->next)
    if(head->data==data) ++counter;
  return counter;
}
```