Integer and Roman Conversion — String Manipulation Patterns
The Integer and Roman Conversion pattern applies when you need the Integer and Roman Conversion technique within the String Manipulation Patterns pattern. Its time complexity is O(1) and space complexity O(1). It is used in 3 problems on Thita, including Integer to Roman, Roman to Integer and String to Integer (atoi). Common variations are Repeated Substring Pattern Detection and Palindrome Check (Two Pointers / Reverse).
Learn to convert between integers and Roman numerals. Essential string manipulation problem.
Integer and Roman Conversion is one of the 6 subpatterns of the String Manipulation Patterns pattern, which covers palindrome checking, anagram detection, pattern matching, and string conversion. The whole pattern is about 2 hours of study. This subpattern is a depth topic for once the core techniques are automatic.
What Integer and Roman Conversion covers
Master string manipulation including palindrome checking, anagram detection, string matching algorithms (KMP, Rabin-Karp), and conversion problems. Problems in this subpattern are usually searched for as roman to integer, integer to roman, roman numeral, number conversion, leetcode 13.
How to practise Integer and Roman Conversion on Thita.ai
Read the theory for Integer and Roman Conversion, then work the problems attached to it in the browser editor. Your solution runs against the problem's test cases, and the AI coach offers a hint about the technique you are missing rather than a finished solution. Progress is tracked per subpattern, so the String Manipulation Patterns tracker shows this one as covered once you have solved its problems.
Other subpatterns in String Manipulation Patterns
- Palindrome Check (Two Pointers / Reverse) — Master palindrome checking using two pointers. Handle valid palindrome with alphanumeric and one removal cases.
- Anagram Check (Frequency Count/Sort) — Master anagram detection using frequency counting and sorting. Group anagrams efficiently.
- Repeated Substring Pattern Detection — Learn to detect if a string can be constructed by repeating a substring pattern.
- Naive / KMP / Rabin-Karp — Master string matching algorithms including naive search, KMP pattern matching, and Rabin-Karp hashing.
- Multiply Strings (Manual Simulation) — Learn to multiply large numbers represented as strings using manual simulation of multiplication.
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.
Where to go next
Integer and Roman Conversion is one lesson in a 16-pattern DSA course. If you are preparing end to end, work the interview-critical patterns first and use the pattern sheet as the checklist; if you are here for one technique, the String Manipulation Patterns guide is the shortest path back to the rest of it.