Approaching (almost) any String Question

As they say, there is no escape from the data structures if you sit down for a coding test!

Data structures can be asked in one form or the other in several coding assessments. From graph interview questions to typical string coding questions, technical assessments cover different data structures appropriately.

One of the most common data structures asked during the tech interviews and tests is the string data structure.

You can understand strings as technical sentences. In technical terms, a set of characters is known as a string.

While applying for different tech interviews, you must have seen a huge quantity of string-based questions in the practice papers and mock tests.

These string coding questions can be a real challenge given their complicated structure and lengthy approaches.

Hence, if you are running out of methods and approaches to resolve these questions through an efficient path, this article contains all the answers to your questions.

This article revolves around various problem-solving approaches and a few operations that you must learn to implement these effective approaches.

Let's initiate our discussion with the basics of strings and understand how strings work.

What are Strings?

Strings are linear data types that store the characters at different indices instead of numbers only (as in arrays). These characters are sequentially placed one after the other throughout the string.

Although the strings are used only for storing characters, the strings technically can contain different characters, symbols, and even numbers.

To make sure that the code understands the sentence or series of characters as a string, it should be placed in between the inverted commas (" ").

Common examples of string include the following formats

• " Hello"

• "Yearis2022"

• "Print@30"

• "AAEEDD"

As you can notice numbers, symbols, and characters inside the quotation mark are simply considered as a part of the string by the code.

There are various operations that you can perform on these strings.

Learning these operations is essential to solving problem statements based on strings. Let's take a glance at different operations that you can apply to the strings.

Must Learn String Operations for Problem Solving Approaches

Similar to the arrays, you can perform different functions on the strings. Following are the most used functions on the strings that further help you to solve the problem statements easily:

• Indexing

In simple terms, indexing can be called pattern matching. Indexing is an operation that helps to locate a pattern in the string from its initial position.

• Concatenation

Also called a connection, this operation is usually used to merge two strings in one. Using this operation, you can arrange the characters of the second string just after the characters of the first string.

• Word Processing

The major operation that will help you resolve string questions is word processing. Different functions such as deletion, insertion, changing the location/index value, and others are included in the word processing operation.

• Substrings

You can divide the larger strings into smaller ones through substrings. This property of strings helps you divide the string into different segments based on the initial letter, length, and location of the characters you wish to arrange in a substring.

Using these operations, the approaches to resolving the string-based questions become quite easy. Let's now discuss these approaches and understands how they will help you get accurate results without much hustle.

Approaches to Solve Different String based questions

Based on the different outputs and requirements, the string-based questions can easily be approached in one of the general ways. The most common and efficient ways of approaching any String-based problem statement are as follows:

• Sliding Window Technique

This technique is quite simple to execute. Usually, you can use this technique whenever you find conditional questions based on strings. Additionally, if the problem statement requires you to analyze the sets of strings at one time, this approach is quite convenient.

The idea of this approach is to set a window first. This window will contain the first and second (beginning and ending respectively) for a string.

Once the window is applied, the operations or conditions are checked on the elements of this window. After it is done, simply the window slides to the next set.

• More pointer approach

Generally, the string is checked from one point either from the beginning or the end. You can use different pointers to analyze the string from different sides. You need to place more than one pointer that points towards either end of the string for a quicker solution.

Mostly, two-pointers are used in this approach with one pointing toward the end of the string and the other pointing toward the beginning.

• Traverse Approach

This approach is specifically efficient while dealing with questions that require you to find the different sets or conditions in a string.

You can traverse the whole string just like the arrays and find the output conditions throughout the traversing process. Traversing the strings is quite an easy and efficient manner of finding the set that adheres to different conditions.

• Backtracking approach

Used for questions involving permutations and specific arrangements, the backtracking approach is efficient and convenient to use.

Questions such as dividing the current string by the Fibonacci series or different equations can easily be solved using the backtracking approach. The idea of this approach is simply to run a loop throughout the string and return the sequences that follow the given conditions.

• Dynamic Programming Approach

If a typical and lengthy problem is on the table, always go for the decrease and conquer approach. Divide your problem into subproblems and resolve these problems through dynamic programming in definite sets.

The idea behind this approach is to identify the subproblem and apply a dynamic programming approach to each subproblem individually

Winding up

Typical questions such as graph interview questions are usually found in every technical assessment. If the typical string coding questions have troubled you in your past tech assessments, defeat the problems with efficient and convenient approaches.

To implement these approaches make sure you learn all the tools and operations carefully.