String Manipulation Patterns — DSA Pattern

The String Manipulation Patterns pattern applies when you need palindrome checking, anagram detection, pattern matching, and string conversion. Its time complexity is O(n) for single-pass or hashing techniques; O(n²) for naive pattern-matching comparisons and space complexity O(1) to O(n), depending on whether extra character counts are tracked. It is used in 13 problems on Thita, including Add Strings, Find Beautiful Indices in the Given Array II and Find the Index of the First Occurrence in a String. Common variations are Repeated Substring Pattern Detection and Palindrome Check (Two Pointers / Reverse).

Master string manipulation including palindrome checking, anagram detection, string matching algorithms (KMP, Rabin-Karp), and conversion problems.

String Manipulation Patterns is pattern 7 of 16 in the Thita.ai DSA course. It covers palindrome checking, anagram detection, pattern matching, and string conversion, split into 6 subpatterns and about 2 hours of study. It is one of the interview-critical patterns, so it is worth covering before your first onsite.

Subpatterns of String Manipulation Patterns

Each subpattern below has its own theory page and problem set. They are listed in the order the course teaches them.

• Palindrome Check (Two Pointers / Reverse) — Master palindrome checking using two pointers. Handle valid palindrome with alphanumeric and one removal cases. (core technique)
• Anagram Check (Frequency Count/Sort) — Master anagram detection using frequency counting and sorting. Group anagrams efficiently. (core technique)
• Repeated Substring Pattern Detection — Learn to detect if a string can be constructed by repeating a substring pattern. (important variation)
• Naive / KMP / Rabin-Karp — Master string matching algorithms including naive search, KMP pattern matching, and Rabin-Karp hashing. (depth topic)
• Integer and Roman Conversion — Learn to convert between integers and Roman numerals. Essential string manipulation problem. (depth topic)
• Multiply Strings (Manual Simulation) — Learn to multiply large numbers represented as strings using manual simulation of multiplication. (depth topic)

How to practise String Manipulation Patterns on Thita.ai

Read the theory for a subpattern, then solve its problems in the browser editor. Your solution runs against the problem's test cases, and the AI coach gives a hint on the technique you are missing rather than the finished answer. Progress is tracked per subpattern, so the tracker shows which of the 6 String Manipulation Patterns subpatterns you have covered. Topics covered here include string manipulation, string algorithms, palindrome check, anagram detection, string matching, KMP algorithm, Rabin-Karp algorithm, string to integer.

Related DSA patterns

• Linked List Manipulation Patterns — In-place reversal, merging sorted lists, reordering, and intersection detection.
• Stack Patterns — Parentheses matching, monotonic stack, histogram, and expression evaluation.
• Tree Traversal Patterns (DFS & BFS) — Preorder, inorder, level order traversal, LCA, and serialization.
• Heap (Priority Queue) Patterns — Top K elements, K-way merge, two heaps for median, and scheduling.
• Greedy Patterns — Interval scheduling, jump games, stock trading, and task scheduling.
• All 16 DSA patterns
• The DSA patterns sheet
• Coding practice