From Crutches to Bijection: How I Wrote a Sudoku Generator in JS

A math teacher in Thailand built a Sudoku grid generator in JavaScript that evolved through multiple versions—from naive shuffling of a base grid using seed-driven geometric transformations, toward strict combinatorics and a full factorial number system (bijection). The article details the first version's approach of applying valid Sudoku-preserving row/column swaps controlled by a hexadecimal seed converted to bit flags.