Irregular NxN Sudoku Solver

An irregular NxN Sudoku (sometimes called Chaos or Jigsaw) is a variation of classic Sudoku where the regions are not necessarily perfect squares. In an irregular Sudoku, these blocks can have more organic or asymmetrical shapes (polyominoes). The goal remains the same: fill the grid with numbers so that each row, each column, and each region contains only one occurrence of each number.

Indicates cells values one by one (it is also possible to make a copy-paste with space as empty cell) as in a classic sudoku.

Only letters or digits are allowed.

Blocks of 9 cells can be selected within predefined examples under the grid or indicated manually by clicking on borders.

The program solves the sudoku, as a human would, and displays each step of its progression for understanding with some explanations. Here are the main steps:

— Initialization: Write down all possible digits for each empty cell.

— Basic Elimination: Remove impossible digits by row, column and region. Find cells with only one possible digit and fill them. Repeat.

— Advanced Techniques: Use patterns (hidden pairs, naked pairs, etc.) to eliminate more digits. Repeat.

— Backtracking (If Necessary): If stuck, try a random digit, see if it works. If it gets stuck, go back and try something else. It is an iterative process of elimination, deduction and, sometimes, trial and error.