Steve Jobs once said, “Everybody should learn to program a computer because it teaches you how to think.” So, when you know how to think, you can generate an idea and turn that idea into a solution. But how do you do that? The short answer is coding. For a layman, coding is just a method of communication between humans and computers. If you know how to code, you can explore the potential of innovation in an increasingly digital world, whether it is creating newer, improved smartphones, laptops, websites, and applications. To become a qualified coder, however, you need relevant skills and certifications. To know how to ace a technical coding interview, explore the list of questions here.
The Best Way to Prepare for a Coding Interview
If you’re looking to get interview-ready for the role of a software engineer, here are some tried-and-tested ways to equip yourself for those coding interviews:
Step1: Select an Appropriate Programming Language
Step 2: Plan, Prioritize, and Practice
Always start with a plan while preparing for a coding interview. Find out how much time you have before your coding test. Then, plan what you must study each day by prioritizing the most important topics and questions. And finally, practice solving problems for those topics to maximize memory retention and efficiency.
Step 3: Prepare an Impressive Introduction
A coding interview begins with you introducing yourself to the interviewer. You should always spend time crafting a good, short introduction to impress interviewers.
ALSO READ: Top 10 Inexpensive Ways to Learn How to Code
Commonly Asked Coding Interview Questions and Answers
1. What is an Array?
An array is a list-like data structure that holds a group of values, each of which is linked to a specific index. An array is one of the most basic data structures in programming and computer science, as well as the building blocks of many more complex data structures. The size of an array as a whole is stagnant.
2. What is a Linked List?
A sequence of data structures that is used to store a collection of data elements is called a linked list. Similar to arrays, it represents sequential data. However, unlike an array, a linked list’s data elements don’t have to be stored in a connected form in memory. Instead, each node in a linked list is equipped with a pointer or reference that pinpoints the location in the memory of the node that comes after it in the list.
3. What is LIFO?
An acronym for ‘last in, first out’, LIFO is a data processing method based on the idea that the items that were put in last will be taken out first and vice versa. The LIFO approach is used to extract data from the data buffer or an array.
4. What is FIFO?
In computer science and systems theory, FIFO stands for ‘first in, first out’ (the first thing that goes in is the first thing to come out) and is the opposite of LIFO. In the FIFO approach to handling a data structure (often a data buffer), the oldest entry, or the ‘head’ of the queue, is handled first.
5. What are Binary Trees?
A binary tree is a type of tree-like, non-linear data structure. Every node in a binary tree has a data element and a left and right reference. The root node is the node at the top of a tree’s hierarchy. Parent nodes are the ones that hold other nodes. Each ‘parent’ can have up to two ‘children’.
6. Differentiate Between Linear and Non-Linear Data Structures.
A linear data structure, with linearly arranged data items, creates a direct connection to its preceding and succeeding elements. The structure facilitates single-level data storage because of its linearity. Examples of this are array, stack, queue, linked list, etc.
On the other hand, non-linear data structures are made up of data elements that are not in a straight line. There is no single level available in a non-linear data structure. So, coders can’t traverse all of the elements in a single run. The implementation of non-linear data structures is more difficult than the more traditionally used linear data structures. A non-linear data structure makes efficient use of the memory available on the computer. Examples of this kind of structure are trees and graphs.
7. How Does Variable Declaration Affect Memory?
Variable declaration affects memory because defining variables occupies space in memory, depending on the type of variable it is. For example, an integer takes up 32 bits of memory. If no values are given, the compiler may assign a variable with the default amount of memory. On the other hand, defining, changing, or accessing a variable can change how much memory it uses.
8. How do You Determine if a String is a Palindrome?
If a string’s reverse is the same as the original, it is said to be a palindrome. For instance, the string ‘abba’ is a palindrome because its reverse will also be ‘abba’, making both of these strings equal. On the other hand, ‘abbc’ is not a palindrome.
Palindromic strings can be verified using a variety of techniques, such as:
- The conventional (basic) approach
- Adopting a C function
- The C reverse and compares functions from the string library
- Employing recursion
9. How do You Find out if Two Strings are Anagrams?
An anagram occurs when two strings have the same set of characters but in different order. This means that the number of times each letter appears must be the same in both strings. An example of an anagram would be the strings ‘act’ and ‘cat’.
You can use C, C++, or Java 8 programs to check if two strings are anagrams by carrying out the following steps:
- Input the two strings in the program
- Make a list of the two strings
- Move through both strings and store the number of letters in each string in its own array
- Check to see if both lists are the same
- Return true if both arrays are the same; else, return false
Let’s understand this with an example.
Input: str1 = “listen” str2 = “silent”
Explanation: All characters of “listen” and “silent” are the same.
Input: str1 = “gram” str2 = “arm”
Output: “Not Anagram”
10. How do You Get the Matching Elements in an Integer Array?
Use the Simple and the Efficient approaches to get the matching elements in an integer array.
The Simple Approach
In this process,sort the given array so that all the equal elements are adjacent to one other. After this, iterate through the array, determining whether or not each pair of adjacent elements is valid by checking their values and skipping the ones that return false.
The Efficient Approach
Make an empty hash table (unordered_map in C++, HashMap in Java, or Dictionary in Python). Keep track of the frequency of each element. Move through the table of hashes. Find out how often each element shows up. For each element, add the frequency/2 to the result.
11. How Would You Swap Two Numbers Without Using a Third Variable?
Swapping two numbers without using a third variable is possible by following either of the two methods—Arithmetic Operatorsor Bitwise XOR.
12. How do You Reverse a Linked List?
The iterative method is used to reverse a linked list. Curr, Prev, and Next are three pointers that are applicable to maintain a track of nodes and update reverse linkages.
13. How Would You Find the Second-Largest Number in an Array?
The most efficient way to find the second-largest number in an array is C++ programming language.
14. Explain Overloading and Overriding with the Help of a Program.
Overriding occurs when the method signature (name and parameters) in the superclass and the child class are identical. However, overloading is the process of having two or more methods in the same class with the same name but with distinct parameters.
Practical Tips for Coding Interviews
In addition to the comprehensive questions and answers, here are some tips to help you do well in your next coding interview.
- Practicing coding problems is the best way to perform well in coding interviews. This will not only train your mind to recognize algorithmic patterns in problems but also give you the confidence to solve problems you have never seen before.
- Learn about data structures and algorithms. For example, if you know about the hash table, you can easily solve several problems that involve arrays and counters.
- Learning about the right data structure is a very important part of software development and coding interviews, and you won’t be able to do it until you know what they are.
- Time yourself. Interviewees who solve problems quickly are more likely to perform well, so you should set time to practice solving coding problems.
Coding is a fundamental skill required to get jobs in the tech industry. If you want to become a coder, enhancing these skills is the best way to find your niche in a tech-savvy world. And Emeritus’ online boot camp and full-stack courses should set you on the path to success.
By Riku Ghosh
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