wordle-solver/README.md

Wordle Solver

This is a toy project to implement a Wordle solver. This project provides no packaging but has no dependencies on libraries that aren't builtin. The main function selects a random word, then simulates the game with the solver and prints the output.

I didn't look at any other solutions before writing this, since that would ruin the fun.

Solver

The solver is mostly brute-force. It takes every possible "guess" word from the dictionary (assumed to be in /etc/share/dict/words), and plays it to every possible "answer" in the dictionary, and determines the top moves. The ranking is based on a heuristic using the average number of remaining playable words, where fewer is better.

Performance is reasonably optimized but the runtime of the overall algorithm is O(n)^3, where n is the size of the dictionary. Using 16 threads I was able to compute the first guess (the slowest) in about 6 hours using a dictionary of 3,000 5-letter words. The subsequent guesses are typically subsecond, and the first guess could be trivially cached since the initial board state is always the same.

Performance Notes

I learned from this project that deepcopy.copy is outrageously slow, even for simple data classes. Initially, it dominated runtime when it was used to copy the board state for each evaluation. I replaced it with a hand-written copy, assigning immutable values and shallow copying dictionaries, and this allowed meeting sufficient performance for a toy.