The ultimate recursion guide! Master basics, solve real-world problems, and get interview-ready in hours with FAANG engineers’ proven strategies.

If you’ve ever struggled with solving coding problems using recursion, or if you need to brush up your recursion skills for an interview, this course is for you! We will start with the basics of recursion before we practice solving actual coding problems. 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 of recursion to solve complex, real-world problems. We hope that this course will help you ace all the recursion related questions during interviews at top tech companies!

Recursion for Coding Interviews in Python

# What does "Power of a Number" mean?
The power (or **exponent**) $a$, of a number $x$ represents the number of times $x$ will be multiplied by itself. It is written as a small, superscript number to the right of and above the **base** number.

For example, if the base number is $2$ and the exponent value is $3$, we represent this as follows:

$2^3 = 8$
​

The following illustration demonstrates this concept further.


To recursively code this problem, we must break it down. We multiply the number with itself in each step.

# Implementation
Let's take a look at the code:

def power(base, exponent):
  # Base Case
  if exponent == 0 :
    return 1
    
  # Recursive Case
  else :
    return base * power(base, exponent - 1);

# Driver Code
print(power(2, 3))

## Explanation
In the code above, the function, `power()`, is recursive, since it makes a recursive call to itself. 

> In recursion, the final solution comprises the solutions to its subtasks.

For example:

$2^3 = 2 * 2^2$

$2^3 = 2 * (2 * 2^1)$

We can generalize this as follows:

$x^a = x * (x)^{a-1}$

$(x)^{a-1} = x * (x)^{a-2}$

$(x)^{a-2} = x * (x)^{a-3}$

.

.

$(x)^{a-a} = 1$

This can be mapped as a recursive function. The last condition $(x)^{a-a} = (x)^{0} = 1$
will be our base case. The rest can be written in the generic format:
$x^a = x * (x)^{a-1}$

Let's take a look at an illustration to better understand how the code is functioning.

In this lesson, we will learn how to find the power of a number using recursion.

Recursion Fundamentals

Iteration Vs. Recursion

Recursion with Numbers

Recursion with Strings

Recursion with Arrays

Recursion with Data Structures

Conclusion

The Power of a Number

What does “Power of a Number” mean?

Implementation

Explanation