Top 50 String Coding Problems for Interviews Last Updated : 23 Jul, 2025 Comments Improve Suggest changes Like Article Like Report String-related problems often assess a candidate's understanding of concepts like pattern matching, manipulation, and efficient algorithm design. Here is the collection of the Top 50 list of frequently asked interview questions on Strings. Problems in this Article are divided into three Levels so that readers can practice according to the difficulty level step by step. Easy Problems Palindrome CheckReverse a String Reverse words in a given string Check for RotationFirst Non Repeating Longest Common Prefix Roman Number to IntegerInteger to RomanClosest StringsDivisible by 7Encrypt the String – IIEqual point in a string of bracketsIsomorphic StringsCheck if two strings are k-anagrams or notPanagram CheckingMinimum DeletionsNumber of Distinct SubsequencesMedium ProblemsImplement Atoi License Key FormattingFind the largest word in dictionaryEqual 0,1, and 2Find and replace in StringAdd Binary StringsSum of two large numbers Multiply two stringsLook and say PatternMinimum times A has to be repeated to make B a SubstringExcel Sheet – IForm a PalindromeFind the N-th characterNext higher palindromic number using the same set of digitsLength of longest prefix suffixLongest K unique characters substringSmallest window in string containing all charactersLongest Palindromic SubsequenceLongest substring without repeating charactersSubstrings of length k with k-1 distinct elementsCount number of substringsInterleaved StringsPrint Anagrams togetherRank the permutationA Special KeyboardHard ProblemsRestrictive Candy CrushEdit DistanceSearch Pattern (KMP-Algorithm)Search Pattern (Rabin-Karp Algorithm) Shortest Common SupersequenceNumber of words with K maximum distinct vowelsLongest substring to form a PalindromeLongest Valid ParenthesisDistinct Palindromic SubstringsRelated Articles:Top 50 Array Coding Problems for InterviewsTop 50 Tree Coding Problems for InterviewsTop 50 Graph Coding Problems for InterviewsTop 50 Dynamic Programming Coding Problems for InterviewsTop 50 Sorting Coding Problems for InterviewsTop 50 Searching Coding Problems for InterviewsTop 50 Binary Search Tree Coding Problems for InterviewsSome other important Tutorials:DSA TutorialSystem Design TutorialSoftware Development RoadmapRoadmap to become a Product ManagerLearn SAPLearn SEO Comment More infoAdvertise with us A abhishek1 Follow Improve Article Tags : Strings DSA GFG Sheets Practice Tags : Strings Explore DSA FundamentalsLogic Building Problems 2 min read Analysis of Algorithms 1 min read Data StructuresArray Data Structure 3 min read String in Data Structure 2 min read Hashing in Data Structure 2 min read Linked List Data Structure 2 min read Stack Data Structure 2 min read Queue Data Structure 2 min read Tree Data Structure 4 min read Graph Data Structure 3 min read Trie Data Structure 15+ min read AlgorithmsSearching Algorithms 2 min read Sorting Algorithms 3 min read Introduction to Recursion 14 min read Greedy Algorithms 3 min read Graph Algorithms 3 min read Dynamic Programming or DP 3 min read Bitwise Algorithms 4 min read AdvancedSegment Tree 2 min read Binary Indexed Tree or Fenwick Tree 15 min read Square Root (Sqrt) Decomposition Algorithm 15+ min read Binary Lifting 15+ min read Geometry 2 min read Interview PreparationInterview Corner 3 min read GfG160 3 min read Practice ProblemGeeksforGeeks Practice - Leading Online Coding Platform 6 min read Problem of The Day - Develop the Habit of Coding 5 min read Like