How to prepare for a coding interview in one month

Review basic data structures and algorithms

Data structures are ways of organising and storing data in a computer so that it can be accessed and modified efficiently. Some basic data structures include:

Arrays: a collection of items stored in contiguous memory locations.

Linked Lists: a collection of items where each item points to the next.

Stack: a last-in, first-out (LIFO) collection of items.

Queue: a first-in, first-out (FIFO) collection of items.

Tree: a hierarchical collection of items, where each item has one parent and zero or more children.

Graph: a collection of items, where each item can point to any other item.

Algorithms are a set of instructions for solving a problem or performing a task. Some basic algorithms include:

Sorting algorithms: algorithms that rearrange a collection of items in a specific order. Examples include Bubble sort, insertion sort, and quicksort.

Search algorithms: algorithms that search for an item in a collection. Examples include linear search and binary search.

Tree traversal algorithms: algorithms that visit all the items in a tree in a specific order. Examples include pre-order, in-order, and post-order traversal.

Graph traversal algorithms: algorithms that visit all the items in a graph in a specific order. Examples include depth-first search and breadth-first search.

Recursion: a method of solving a problem by breaking it down into smaller, identical problems.

Dynamic Programming: a method of solving a problem by breaking it down into simpler subproblems and storing their solutions to avoid redundant work.

Greedy Algorithm: a method of solving a problem by making locally optimal choices at each stage with the hope of finding a global optimum.

Keep in mind that this is just a very basic overview, and there are many more data structures and algorithms available depending on the type of problem you’re trying to solve.

Practice coding problems

Try to solve as many coding problems as possible.

LeetCode (leetcode.com) is a website that hosts a large collection of coding problems and allows you to submit solutions in several programming languages. It also has a feature that simulates a coding interview.

HackerRank (hackerrank.com) is another website that hosts coding problems and competitions. It also has a feature that simulates a coding interview.

Interviewbit (interviewbit.com) is a website that provides a platform for coding practice and interview preparation. It also has a feature that simulates a coding interview.

Pramp (pramp.com) is a peer-to-peer platform that connects you with other people for a practice coding interview.

Coderust (coderust.com) is a book that provides a guide to coding interview with a large collection of problems and solutions.

Understand problem-solving strategies

Understand the problem: Make sure you understand the problem statement and the requirements. Ask clarifying questions if needed.

Break down the problem: Identify the sub-problems that make up the overall problem and tackle them one by one.

Use examples and edge cases: Come up with examples and edge cases to test your solution. This will help you identify any gaps in your understanding of the problem.

Use brute force: If you are stuck, try using a brute force solution to get a basic understanding of the problem.

Optimize your solution: Once you have a working solution, think about how to optimize it for better performance or less memory usage.

Communicate your thought process: During the interview, it is important to clearly communicate your thought process and explain your reasoning for choosing certain approaches.

Practice: Practice coding problems and algorithms to improve your problem-solving skills and increase your confidence during the interview.

Practice with mock interviews

It is important to practice on as many different types of problems as possible, and to get feedback on your solutions from others in order to improve your skills. Additionally, try to practice under time pressure to get used to the feeling of a real interview.

Read about common interview questions

Familiarize yourself with common interview questions and the types of problems that are likely to be asked.

Here are some common coding interview questions that you may encounter during a technical interview for a software developer or engineer role:

Reverse a string: Write a function that takes a string as input and returns the reverse of the string.

Find the first non-repeated character in a string: Write a function that takes a string as input and returns the first non-repeated character in the string.

Find the majority element in an array: Given an array of integers, write a function that finds the majority element (the element that appears more than half the time) in the array.

Implement a binary search: Write a function that takes in a sorted array and a value and returns the index of the value in the array. If the value is not in the array, return -1.

Implement a linked list: Write a class that represents a singly-linked list, with methods for adding and removing nodes, as well as finding the length of the list.

Implement a stack: Write a class that represents a stack, with methods for pushing and popping elements, as well as finding the size of the stack.

Implement a queue: Write a class that represents a queue, with methods for enqueuing and dequeuing elements, as well as finding the size of the queue.

Implement a tree: Write a class that represents a tree, with methods for adding and removing nodes, as well as finding the depth of the tree.

Find the two numbers that sum to a given target: Given an array of integers and a target value, write a function that finds the two numbers in the array that add up to the target value.

Find the median of two sorted arrays: Given two sorted arrays, write a function that finds the median element.

These are just a few examples of the types of questions you may encounter in a coding interview. It is important to practice solving these types of problems and to be familiar with the data structures and algorithms that are commonly used to solve them.

Keep yourself updated with the company

Learn about the company you are interviewing with, their product and mission.

Note that this is a general outline and the time required may vary depending on your current level of knowledge and experience. Also, it’s important to remember that the interview process is not just about solving problems, but also about communicating your thought process, understanding the requirements of the problem and working collaboratively with the interviewer.