String, Subsequence & Substring (original) (raw)

• String in Data Structure A string is a sequence of characters. The following facts make string an interesting data structure. Small set of elements. Unlike normal array, strings typically have smaller set of items. For example, lowercase English alphabet has only 26 characters. ASCII has only 256 characters.Strings are immu 3 min read
• Introduction to Strings - Data Structure and Algorithm Tutorials Strings are sequences of characters. The differences between a character array and a string are, a string is terminated with a special character ‘\0’ and strings are typically immutable in most of the programming languages like Java, Python and JavaScript. Below are some examples of strings: "geeks" 7 min read
• Applications, Advantages and Disadvantages of String The String data structure is the backbone of programming languages and the building blocks of communication. String data structures are one of the most fundamental and widely used tools in computer science and programming. They allow for the representation and manipulation of text and character sequ 6 min read
• String, Subsequence & Substring What is a Substring? A substring is a contiguous part of a string, i.e., a string inside another string. In general, for an string of size n, there are n*(n+1)/2 non-empty substrings. For example, Consider the string "geeks", There are 15 non-empty substrings. The subarrays are: g, ge, gee, geek, ge 6 min read
• Storage for Strings in C In C, a string can be referred to either using a character pointer or as a character array. Strings as character arrays [GFGTABS] C char str[4] = "GfG"; /*One extra for string terminator*/ /* OR */ char str[4] = {‘G’, ‘f’, ‘G’, '\0'}; /* '\0' is string terminator */ [/GFGTA 5 min read

Strings in different language

• Strings in C A String in C programming is a sequence of characters terminated with a null character '\0'. The C String is work as an array of characters. The difference between a character array and a C string is that the string in C is terminated with a unique character '\0'. DeclarationDeclaring a string in C 5 min read

• std::string class in C++ C++ has in its definition a way to represent a sequence of characters as an object of the class. This class is called std:: string. The string class stores the characters as a sequence of bytes with the functionality of allowing access to the single-byte character. String vs Character ArrayString Ch 8 min read

• String Class in Java A string is a sequence of characters. In Java, objects of the String class are immutable, which means they cannot be changed once created. In this article, we are going to learn about the String class in Java. Example of String Class in Java: [GFGTABS] Java // Java Program to Create a String import 7 min read

• Python String A string is a sequence of characters. Python treats anything inside quotes as a string. This includes letters, numbers, and symbols. Python has no character data type so single character is a string of length 1. [GFGTABS] Python s = "GfG" print(s[1]) # access 2nd char s1 = s + s[0] # updat 6 min read

• C# Strings In C#, a string is a sequence of Unicode characters or an array of characters. The range of Unicode characters will be U+0000 to U+FFFF. The array of characters is also termed as the text. So the string is the representation of the text. A string is an important concept, and sometimes people get con 8 min read

• JavaScript String Methods JavaScript strings are the sequence of characters. They are treated as Primitive data types. In JavaScript, strings are automatically converted to string objects when using string methods on them. This process is called auto-boxing. The following are methods that we can call on strings. slice() extr 12 min read

• PHP Strings In PHP, strings are one of the most commonly used data types. A string is a sequence of characters used to represent text, such as words and sentences. Strings are enclosed in either single quotes (' ') or double quotes (" "). You can create a string using single quotes (' ') or double quotes (" "). 4 min read

Basic operations on String

• Searching For Characters and Substring in a String in Java Efficient String manipulation is very important in Java programming especially when working with text-based data. In this article, we will explore essential methods like indexOf(), contains(), and startsWith() to search characters and substrings within strings in Java. Searching for a Character in a 5 min read

• Reverse a String – Complete Tutorial Given a string s, the task is to reverse the string. Reversing a string means rearranging the characters such that the first character becomes the last, the second character becomes second last and so on. Examples: Input: s = "GeeksforGeeks"Output: "skeeGrofskeeG"Explanation : The first character G 14 min read

• Left Rotation of a String Given a string s and an integer d, the task is to left rotate the string by d positions. Examples: Input: s = "GeeksforGeeks", d = 2Output: "eksforGeeksGe" Explanation: After the first rotation, string s becomes "eeksforGeeksG" and after the second rotation, it becomes "eksforGeeksGe". Input: s = "q 15+ min read

• Sort string of characters Given a string of lowercase characters from 'a' - 'z'. We need to write a program to print the characters of this string in sorted order. Examples: Input : "dcab" Output : "abcd"Input : "geeksforgeeks"Output : "eeeefggkkorss" Naive Approach - O(n Log n) TimeA simple approach is to use sorting algori 5 min read

• Frequency of Characters in Alphabetical Order Given a string s, the task is to print the frequency of each of the characters of s in alphabetical order.Example: Input: s = "aabccccddd" Output: a2b1c4d3 Since it is already in alphabetical order, the frequency of the characters is returned for each character. Input: s = "geeksforgeeks" Output: e4 9 min read

• Swap characters in a String Given a String S of length N, two integers B and C, the task is to traverse characters starting from the beginning, swapping a character with the character after C places from it, i.e. swap characters at position i and (i + C)%N. Repeat this process B times, advancing one position at a time. Your ta 14 min read

• C Program to Find the Length of a String The length of a string is the number of characters in it without including the null character (‘\0’). In this article, we will learn how to find the length of a string in C. The easiest way to find the string length is by using strlen() function from the C strings library. Let's take a look at an ex 2 min read

• How to insert characters in a string at a certain position? Given a string str and an array of indices chars[] that describes the indices in the original string where the characters will be added. For this post, let the character to be inserted in star (*). Each star should be inserted before the character at the given index. Return the modified string after 7 min read

• Check if two strings are same or not Given two strings, the task is to check if these two strings are identical(same) or not. Consider case sensitivity. Examples: Input: s1 = "abc", s2 = "abc" Output: Yes Input: s1 = "", s2 = "" Output: Yes Input: s1 = "GeeksforGeeks", s2 = "Geeks" Output: No Approach - By Using (==) in C++/Python/C#, 7 min read

• Concatenating Two Strings in C Concatenating two strings means appending one string at the end of another string. In this article, we will learn how to concatenate two strings in C. The most straightforward method to concatenate two strings is by using strcat() function. Let's take a look at an example: [GFGTABS] C #include <s 3 min read

• Remove all occurrences of a character in a string Given a string and a character, remove all the occurrences of the character in the string. Examples: Input : s = "geeksforgeeks" c = 'e'Output : s = "gksforgks"Input : s = "geeksforgeeks" c = 'g'Output : s = "eeksforeeks"Input : s = "geeksforgeeks" c = 'k'Output : s = "geesforgees" Using Built-In Me 2 min read

Binary String

• Check if all bits can be made same by single flip Given a binary string, find if it is possible to make all its digits equal (either all 0's or all 1's) by flipping exactly one bit. Input: 101Output: YeExplanation: In 101, the 0 can be flipped to make it all 1 Input: 11Output: NoExplanation: No matter whichever digit you flip, you will not get the 5 min read

• Number of flips to make binary string alternate | Set 1 Given a binary string, that is it contains only 0s and 1s. We need to make this string a sequence of alternate characters by flipping some of the bits, our goal is to minimize the number of bits to be flipped. Examples : Input : str = “001” Output : 1 Minimum number of flips required = 1 We can flip 8 min read

• Binary representation of next number Given a binary string that represents binary representation of positive number n, the task is to find the binary representation of n+1. The binary input may or may not fit in an integer, so we need to return a string. Examples: Input: s = "10011"Output: "10100"Explanation: Here n = (19)10 = (10011)2 6 min read

• Min flips of continuous characters to make all characters same in a string Given a string consisting only of 1's and 0's. In one flip we can change any continuous sequence of this string. Find this minimum number of flips so the string consist of same characters only.Examples: Input : 00011110001110Output : 2We need to convert 1's sequenceso string consist of all 0's.Input 8 min read

• Generate all binary strings without consecutive 1's Given an integer n, the task is to generate all binary strings of size n without consecutive 1's. Examples: Input : n = 4Output : 0000 0001 0010 0100 0101 1000 1001 1010 Input : n = 3Output : 000 001 010 100 101 Approach: The idea is to generate all binary strings of length n without consecutive 1's 6 min read

• Find i'th Index character in a binary string obtained after n iterations Given a decimal number m, convert it into a binary string and apply n iterations. In each iteration, 0 becomes "01" and 1 becomes "10". Find the (based on indexing) index character in the string after the nth iteration. Examples: Input : m = 5, n = 2, i = 3Output : 1Input : m = 3, n = 3, i = 6Output 6 min read

Substring and Subsequence

• All substrings of a given String Given a string s, containing lowercase alphabetical characters. The task is to print all non-empty substrings of the given string. Examples : Input : s = "abc"Output : "a", "ab", "abc", "b", "bc", "c" Input : s = "ab"Output : "a", "ab", "b" Input : s = "a"Output : "a" [Expected Approach] - Using Ite 9 min read

• Print all subsequences of a string Given a string, we have to find out all its subsequences of it. A String is said to be a subsequence of another String, if it can be obtained by deleting 0 or more character without changing its order. Examples: Input : abOutput : "", "a", "b", "ab" Input : abcOutput : "", "a", "b", "c", "ab", "ac", 12 min read

• Count Distinct Subsequences Given a string str of length n, your task is to find the count of distinct subsequences of it. Examples: Input: str = "gfg"Output: 7Explanation: The seven distinct subsequences are "", "g", "f", "gf", "fg", "gg" and "gfg" Input: str = "ggg"Output: 4Explanation: The four distinct subsequences are "", 14 min read

• Count distinct occurrences as a subsequence Given two strings pat and txt, where pat is always shorter than txt, count the distinct occurrences of pat as a subsequence in txt. Examples: Input: txt = abba, pat = abaOutput: 2Explanation: pat appears in txt as below three subsequences.[abba], [abba] Input: txt = banana, pat = banOutput: 3Explana 15+ min read

• Longest Common Subsequence (LCS) Given two strings, s1 and s2, the task is to find the length of the Longest Common Subsequence. If there is no common subsequence, return 0. A subsequence is a string generated from the original string by deleting 0 or more characters, without changing the relative order of the remaining characters. 15+ min read

• Shortest Superstring Problem Given a set of n strings arr[], find the smallest string that contains each string in the given set as substring. We may assume that no string in arr[] is substring of another string.Examples: Input: arr[] = {"geeks", "quiz", "for"}Output: geeksquizforExplanation: "geeksquizfor" contains all the thr 15+ min read

• Printing Shortest Common Supersequence Given two strings s1 and s2, find the shortest string which has both s1 and s2 as its sub-sequences. If multiple shortest super-sequence exists, print any one of them.Examples: Input: s1 = "geek", s2 = "eke"Output: geekeExplanation: String "geeke" has both string "geek" and "eke" as subsequences.Inp 9 min read

• Shortest Common Supersequence Given two strings s1 and s2, the task is to find the length of the shortest string that has both s1 and s2 as subsequences. Examples: Input: s1 = "geek", s2 = "eke"Output: 5Explanation: String "geeke" has both string "geek" and "eke" as subsequences. Input: s1 = "AGGTAB", s2 = "GXTXAYB"Output: 9Expl 15+ min read

• Longest Repeating Subsequence Given a string s, the task is to find the length of the longest repeating subsequence, such that the two subsequences don't have the same string character at the same position, i.e. any ith character in the two subsequences shouldn't have the same index in the original string. Examples: Input: s= "a 15+ min read

• Longest Palindromic Subsequence (LPS) Given a string s, find the length of the Longest Palindromic Subsequence in it. Note: The Longest Palindromic Subsequence (LPS) is the maximum-length subsequence of a given string that is also a Palindrome. Examples: Input: s = "bbabcbcab"Output: 7Explanation: Subsequence "babcbab" is the longest su 15+ min read

• Longest Palindromic Substring Given a string s, the task is to find the longest substring which is a palindrome. If there are multiple answers, then return the first appearing substring. Examples: Input: s = "forgeeksskeegfor" Output: "geeksskeeg"Explanation: There are several possible palindromic substrings like "kssk", "ss", " 12 min read

Palindrome

• C Program to Check for Palindrome String A string is said to be palindrome if the reverse of the string is the same as the string. In this article, we will learn how to check whether the given string is palindrome or not using C program. The simplest method to check for palindrome string is to reverse the given string and store it in a tem 4 min read

• Check if a given string is a rotation of a palindrome Given a string, check if it is a rotation of a palindrome. For example your function should return true for "aab" as it is a rotation of "aba". Examples: Input: str = "aaaad" Output: 1 // "aaaad" is a rotation of a palindrome "aadaa" Input: str = "abcd" Output: 0 // "abcd" is not a rotation of any p 15+ min read

• Check if characters of a given string can be rearranged to form a palindrome Given a string, Check if the characters of the given string can be rearranged to form a palindrome. For example characters of "geeksogeeks" can be rearranged to form a palindrome "geeksoskeeg", but characters of "geeksforgeeks" cannot be rearranged to form a palindrome. Recommended PracticeAnagram P 14 min read

• Online algorithm for checking palindrome in a stream Given a stream of characters (characters are received one by one), write a function that prints 'Yes' if a character makes the complete string palindrome, else prints 'No'. Examples: Input: str[] = "abcba"Output: a Yes // "a" is palindrome b No // "ab" is not palindrome c No // "abc" is not palindro 15+ min read

• Print all Palindromic Partitions of a String using Bit Manipulation Given a string, find all possible palindromic partitions of a given string. Note that this problem is different from Palindrome Partitioning Problem, there the task was to find the partitioning with minimum cuts in input string. Here we need to print all possible partitions. Example: Input: nitinOut 10 min read

• Minimum Characters to Add at Front for Palindrome Given a string s, the task is to find the minimum number of characters to be added to the front of s to make it palindrome. A palindrome string is a sequence of characters that reads the same forward and backward. Examples: Input: s = "abc"Output: 2Explanation: We can make above string palindrome as 12 min read

• Make largest palindrome by changing at most K-digits You are given a string s consisting of digits (0-9) and an integer k. Convert the string into a palindrome by changing at most k digits. If multiple palindromes are possible, return the lexicographically largest one. If it's impossible to form a palindrome with k changes, return "Not Possible". Exam 14 min read

• Minimum Deletions to Make a String Palindrome Given a string s of length n, the task is to remove or delete the minimum number of characters from the string so that the resultant string is a palindrome. Note: The order of characters should be maintained. Examples : Input : s = "aebcbda"Output : 2Explanation: Remove characters 'e' and 'd'. Resul 15+ min read

• Minimum insertions to form a palindrome with permutations allowed Given a string of lowercase letters. Find minimum characters to be inserted in the string so that it can become palindrome. We can change the positions of characters in the string. Examples: Input: geeksforgeeksOutput: 2Explanation: geeksforgeeks can be changed as: geeksroforskeeg or geeksorfroskeeg 5 min read