String in Data Structure

In data structures, a string is a sequence of characters used to represent text. Strings are commonly used for storing and manipulating textual data in computer programs. They can be manipulated using various operations like concatenation, substring extraction, and comparison.

String in Data Structure

What is a String?

String is considered a data type in general and is typically represented as arrays of bytes (or words) that store a sequence of characters. String is defined as an array of characters. The difference between a character array and a string is the string is terminated with a special character ‘\0’. Some examples of strings are: “geeks” , “for”, “geeks”, “GeeksforGeeks”, “Geeks for Geeks”, “123Geeks”, “@123 Geeks”.

String Data Type:

In most programming languages, strings are treated as a distinct data type. This means that strings have their own set of operations and properties. They can be declared and manipulated using specific string-related functions and methods.

Note: In some languages, strings are implemented as arrays of characters, making them a derived data type.

String Operations:

Strings support a wide range of operations, including concatenation, substring extraction, length calculation, and more. These operations allow developers to manipulate and process string data efficiently.

Below are fundamental operations commonly performed on strings in programming.

• Concatenation: Combining two strings to create a new string.
• Length: Determining the number of characters in a string.
• Access: Accessing individual characters in a string by index.
• Substring: Extracting a portion of a string.
• Comparison: Comparing two strings to check for equality or order.
• Search: Finding the position of a specific substring within a string.
• Modification: Changing or replacing characters within a string.

Applications of String:

• Text Processing: Strings are extensively used for text processing tasks such as searching, manipulating, and analyzing textual data.
• Data Representation: Strings are fundamental for representing and manipulating data in formats like JSON, XML, and CSV.
• Encryption and Hashing: Strings are commonly used in encryption and hashing algorithms to secure sensitive data and ensure data integrity.
• Database Operations: Strings are essential for working with databases, including storing and querying text-based data.
• Web Development: Strings are utilized in web development for constructing URLs, handling form data, processing input from web forms, and generating dynamic content.

Basics of Strings:

• Introduction to Strings – Data Structure and Algorithm Tutorials
• Applications, Advantages and Disadvantages of String
• Storage for Strings in C

String in different language:

• Strings in C
• String Class in C++
• String Class in Java
• Python String
• C# | String
• JavaScript String
• PHP | Strings

Basic Operations of String:

• Searching For Characters and Substring in a String
• Program to reverse a string (Iterative and Recursive)
• Left Rotation and Right Rotation of a String
• Sort string of characters
• Print the frequency of each character in Alphabetical order
• Swap characters in a String
• C program to find the length of a string
• How to insert characters in a string at a certain position?
• Program to check if two strings are same or not
• Concatenating Two Strings
• Remove all occurrences of a character in a string

Binary String:

• Change if all bits can be made same by single flip
• Number of flips to make binary string alternate
• Binary representation of next number
• Min flips of continuous characters to make all characters same in a string
• Generate all binary strings without consecutive 1’s
• Find i’th Index character in a binary string obtained after n iterations
• Generate n-bit Gray Codes

Substring & Subsequence:

• Program to print all substrings of a given string
• Print all subsequences of a string
• Count Distinct Subsequences
• Count distinct occurrences as a subsequence
• Longest Common Subsequence
• Shortest Superstring Problem
• Printing Shortest Common Supersequence
• Shortest Common Supersequence
• Longest Repeating Subsequence
• Longest Palindromic Subsequence
• Longest Palindromic Substring using Dynamic Programming

Pattern Searching:

• Naive algorithm for Pattern Searching
• KMP Algorithm for Pattern Searching
• Z algorithm
• Search a Word in a 2D Grid of characters
• Wildcard Pattern Matching
• Aho-Corasick Algorithm
• Find all strings that match specific pattern in a dictionary
• Check if string follows order of characters defined by a pattern or not

Problems on Palindrome String:

• C Program to Check if a Given String is Palindrome
• Check if a given string is a rotation of a palindrome
• Check if characters of a given string can be rearranged to form a palindrome
• Online algorithm for checking palindrome in a stream
• Print all palindromic partitions of a string
• Minimum characters to be added at front to make string palindrome
• Make largest palindrome by changing at most K-digits
• Minimum number of deletions to make a string palindrome
• Minimum insertions to form a palindrome with permutations allowed

Easy Problems on String:

• Count strings with consecutive 1’s
• Generate all binary strings from given pattern
• Add n binary strings
• Divide large number represented as string
• Program to find Smallest and Largest Word in a String
• Count number of equal pairs in a string
• Camel case of a given sentence
• Second most repeated word in a sequence
• Print all possible strings that can be made by placing spaces
• Check if all levels of two trees are anagrams or not

Medium Problems on String:

• K’th Non-repeating Character
• Queries for characters in a repeated string
• URLify a given string (Replace spaces is %20)
• Count of total anagram substrings
• Count number of binary strings without consecutive 1’s
• Lexicographically next string
• Check if given string can be split into four distinct strings
• Word Break Problem
• Check for balanced parentheses in an expression | O(1) space
• Length of Longest Balanced Subsequence
• Minimum Swaps for Bracket Balancing
• Convert a sentence into its equivalent mobile numeric keypad sequence
• Burrows – Wheeler Data Transform Algorithm
• Form minimum number from given sequence
• Print shortest path to print a string on screen
• Mirror characters of a string

Hard Problems on String:

• Multiply Large Numbers represented as Strings
• Count ways to increase LCS length of two strings by one
• Minimum rotations required to get the same string
• Find if an array of strings can be chained to form a circle
• Given a sorted dictionary of an alien language, find order of characters
• Remove minimum number of characters so that two strings become anagram
• Minimum Number of Manipulations required to make two Strings Anagram Without Deletion of Character
• Palindrome Substring Queries
• Powet Set in Lexicographic order
• Minimum Word Break
• Minimum number of bracket reversals needed to make an expression balanced
• Word Wrap problem ( Space optimized solution )
• Decode a string recursively encoded as count followed by substring