Recurrify — Recurrence Relation Solver & Explainer

Overview

Recurrify is a full-stack educational tool for algorithm students. Enter any recurrence relation and get step-by-step solutions rendered in beautiful LaTeX math. The backend uses a hand-written recursive descent parser (tokenizer → parser → AST → SymPy bridge) to parse arbitrary recurrence relations and classify them for the appropriate solving method.

Key Features

• Multi-Method Solving — Master Theorem (3 cases), Recursion Tree with level-cost tables, Iteration/Telescoping with pattern display, and Characteristic Equation for linear recurrences
• Step-by-Step Derivations — Every solution shows the full reasoning chain from initial recurrence to closed-form, all rendered in LaTeX via KaTeX
• Symbolic & Numeric Verification — Substitutes closed forms back into the original recurrence to prove correctness, and computes actual values for comparison
• Guided Reasoning Mode — Interactive Q&A that walks students through the solving process with a state-machine-driven question bank
• 8 Built-in Examples — Merge Sort, Binary Search, Karatsuba, Strassen, Fibonacci, and more

Technical Highlights

• Backend: Python 3.11 + FastAPI with SymPy for symbolic math — simplification, limits, and LaTeX generation
• Parser: Custom recursive descent parser with regex-based lexer, frozen dataclass AST nodes, and Pydantic validation
• Frontend: React 18 + TypeScript + Vite with KaTeX rendering and a dark glassmorphism-inspired UI
• Testing: 37 tests across tokenizer, parser, solvers, and async API integration