If you’ve ever struggled with solving problems using recursion, or if you have to brush up your skills for an interview, this course is for you.

We'll start with the basics of what recursion is and why it’s important before diving into practicing solving actual questions. You’ll have access to detailed explanations and visualizations for each problem to help you along the way. 

By the time you have completed this course, you’ll be able to use all the concepts to solve complex real-world problems. We hope that through practicing recursion, you will be able to ace all recursion related questions in interviews at top tech companies.

Solving Problems with Recursion in Python

## Problem Statement
Implement a function that takes a linked list `testVariable` and returns the length of the linked list.

### Input
1. A variable `testVariable` containing the linked list whose length needs to be calculated.
2. The head node of the linked list `head`.

### Output
Length of the input linked list

### Sample Input
```
testVariable => 3 -> 4 -> 7 -> 11 -> None
head => 3
```
### Sample Output
```
4
```

### Try it Yourself
Try to attempt this challenge by yourself before moving on to the solution. Good luck!



import node as n

class LinkedList: 
	def __init__(self) :
		self.head = None

	def append(self, new_data): 
		new_node = n.Node(new_data) 
		
		if self.head is None : # If head node is null 
			self.head = new_node 
			return

		last = self.head 
		while (last.next): 
			last = last.next
		last.next =  new_node # add new node to end of list

	def printList(self):
		temp = self.head
		while(temp):
			print(temp.data)
			temp = temp.next

class Node: 
	def __init__(self, data): 
		self.data = data 
		self.next = None


import linkedList as l

def length(testVariable, head) :
	# Write your code here
	return None

import linkedList as l

def length(testVariable, head) :
	if (not head) :
		return 0
		
	else :
		return 1 + length(testVariable, head.next) 

---
In the next lesson, we have a solution review of this problem.

# Problem Statement
Implement a function that takes a linked list `testVariable` and returns the length of the linked list.

## Input
1. A variable `testVariable` containing the linked list whose length needs to be calculated.
2. The head node of the linked list `head`.

## Output
Length of the input linked list

## Sample Input
```
testVariable => 3 -> 4 -> 7 -> 11 -> None
head => 3
```
## Sample Output
```
4
```

## Try it Yourself
Try to attempt this challenge by yourself before moving on to the solution. Good luck!



Find the length of the given linked list.

Recursion Fundamentals

Iteration Vs. Recursion

Recursion with Numbers

Recursion with Strings

Recursion with Arrays

Recursion with Data Structures

Conclusion

Challenge 1: Length of a Linked List

Problem Statement

Input

Output

Sample Input

Sample Output

Try it Yourself