Essay Problem Solving
Generating Functions for Competitive Combinatorics
How algebraic manipulation of power series solves combinatorial recurrences instantly.
Problem Solving · String Algorithms
A blog and newsletter on Competitive programming techniques and IOI-style problem breakdowns.
Essay String Algorithms
Z-Function vs KMP Failure Function in String Problems
Z-function works forward, KMP looks back—pick the one that matches your problem's natural direction.
A recurrence comes in, a generating function goes out, and the coefficients fall out of the algebra.