Top 10 String Questions from Coding Interviews

String questions form an integral part of your coding interviews!

These questions are a way to judge your rock-solid foundation on data structures.

Preparing hard for these questions will pave the way for higher job chances in your dream tech giant!

From FAANG to MAANG companies, string-based code questions often appear to test the coding strength of desired candidates.

Keeping the gruesome need of these questions in consideration, we have curated this blog post.

Here, you will come to know about some of the most commonly string related questions that you are highly likely to encounter in an upcoming interview.

Without any ado, let’s get started with it!

Strings - A Glimpse

String interview questions have the high chances to appear as De Shaw online test questions or other top giant’s interview questions.

It is a vital data structure that is found in almost all the programming languages like Python, C , C++ and more. Though, the implementation of string may differ but the essence of it stays the same as strings are touted as the null terminated characters.

In the interview rounds, questions on strings, its structure, reversing a given string, checking if it is palindrome and other such questions may appear. The string questions in coding interviews may vary based on the level of difficulty and choice of interviewer.

However, you need to be fully prepared for the string related questions to ace your interview.

Top String Questions

Get to know about some of the most common questions related to strings that may be asked from you in the upcoming coding interview.

1. How can you print the duplicate characters in a given string?

You can write the program in C, C++, Java or python in order to print certain duplicate characters in the string.

Take an example; If the given string is java, the program shall be printed as “a”. Get bonus points when the program handles various types of output like springs without the duplicates or null or empty strings.

2. Check if the given two strings are anagrams or not

This is a coding problem which can also be used with the help of numbers. You can write the java program to check whether two strings are the anagrams of themselves or not. They are anagrams when they are being written by using the same letters while ignoring all the spaces or capitalization. All its letters need to have the same count in the strings.

3. How to reverse a given string using the iteration and recursion?

You need to write a program in order to reverse java strings without the usage of StringBuffer. For the string reversal, you can use both the recursion and iterative algorithms. You can use methods of string utility. For example; charAt(), substring(), toCharArray()

4. Check if a given string contains digits?

You have to write the program for checking if the string only contains numbers by using regular java expressions. You can also make use of the Java API as this is what an interviewer can expect you to do.

5. Count all vowels or consonants in the string?

For this, you can write the java program that will take up the string input in order to print vowels or consonants in the string. For example; in case the given input is “java”, your program will print as “2 vowels, 2 consonants”

If you get the answer, you need to clear if the string has numbers or characters or anything else than it.

6. How can you count occurrences of a character in the string?

If an interviewer asks as an aspirant to ask the occurrences of any character with the use of any hash tables, arrays or data structures. To solve the problem, you can do it.

For example; if the given input string is considered Java, and the given character is “a”, it should return the value 2. Bonus points if the handle case is null with the empty string and come up with its unit tests.

7. How to convert the numeric string to the int?

The classical coding interview question is based on the string. You can write the method of atoi() with C, C++ and take up the numeric string.

For example; if you pass the “67263” with the program, it will return 67263.

8. Program to print the first non-repeated characters from the given string

You need to find the first unique characters in a given string, for instance; if the string is “Morning, it can print M. The question will demonstrate effective use of hashtables.

We can perform the string from its left to right counting with the number of occurrences in the characters in a hash table. We can perform the second pass to check the count in every character. Whenever, we can hit the count 1 to return the characters so that you can get the first sequence of a unique letter.

9. How to find the permutations of a given string?

This is considered as the easy recursive solution. Though, it can be really tricky when an interviewer will ask you to solve questions without the usage of recursion. You can write the programs to print the permutations in a string. For example; if an input is “xyz” , you can print, xyz, zxy, xzy, yxz, zyx.

10. Edit distance

Two strings S and T of length N and M are given to you. Find “edit distance” within the given string. Though, the edit distance of two strings with the minimum steps are required to make a string equal to others. In order to do it, you can perform three operations by deleting the character, replacing the character with another one or inserting the characters.

Wrapping Up

String questions are most commonly asked questions such as the De Shaw online test questions and other company’s interview questions.

Keep this guide as a mentor to prepare well for the string r

elated questions by making your basics clear and foundation strongs.

Practise well, work hard and slay your interviews!