Wordle Solver

Weekend project to come up with automated strategies to solve Wordle.

High water mark of my solver:

Solves dictionary with 99.83% success rate, 3.66696 average guesses in under 3 seconds.

Setup

$ cmake -DCMAKE_BUILD_TYPE=Release .
$ time make
[ 16%] Building CXX object CMakeFiles/solver.dir/wordle_selector.cpp.o
[ 33%] Building CXX object CMakeFiles/solver.dir/wordlist_wordle_solver.cpp.o
[ 50%] Building CXX object CMakeFiles/solver.dir/wordle_trie.cpp.o
[ 66%] Building CXX object CMakeFiles/solver.dir/wordle_checker.cpp.o
[ 83%] Building CXX object CMakeFiles/solver.dir/main.cpp.o
[100%] Linking CXX executable solver
[100%] Built target solver

real	0m9.517s
user	0m8.867s
sys 	0m0.521s

How to Use

• Solve Entire Dictionary

$ time ./solver --mode all
Wordle Solver v4
mode:all

guess1cands,guess2cands,guess3cands,guess4cands,guess5cands,guess6cands,result,words_left,num_guesses,answer
2315,48,4,3,2,1,success,1,6,aback
2315,6,2,1,1,1,success,1,4,abase
2315,6,3,2,1,1,success,2,4,abate
2315,61,1,1,1,1,success,1,3,abbey
2315,51,4,1,1,1,success,1,4,abbot
2315,136,15,2,1,1,success,1,5,abhor
...
2294/2315=0.9909
done.

real	0m11.157s
user	0m10.390s
sys 	0m0.698s

• Solve Entire Dictionary, Fast

$ time ./solver --mode all --multi
Wordle Solver v4
mode:all

guess1cands,guess2cands,guess3cands,guess4cands,guess5cands,guess6cands,result,words_left,num_guesses,answer
2315,48,4,3,2,1,success,1,6,aback
2315,6,2,1,1,1,success,1,4,abase
2315,6,3,2,1,1,success,2,4,abate
2315,61,1,1,1,1,success,1,3,abbey
2315,51,4,1,1,1,success,1,4,abbot
2315,136,15,2,1,1,success,1,5,abhor
...
2294/2315=0.9909
done.

real	0m2.577s
user	0m19.079s
sys 	0m1.619s

• Original Interactive Mode

$ ./solver --mode interactive
Wordle Solver v4
mode:interactive

Guess #1: sling
> GBGBB
Guess #2: shiny
> GGGBB
Guess #3: shirk
> GGGGG
Success!
Wordle 3/7

• Debug Mode (#define DEBUG_UNICODE=true for pretty print)

$ ./solver --mode debug --word brain
Wordle Solver v4
mode:debug

⬛⬛🟨🟩🟩
⬛⬛⬛🟩🟩
🟩🟩🟩🟩🟩
Wordle 3/6

• Cheat Mode

$ ./solver --mode cheat
Wordle Solver v4
Size of wordlist: 2315
Size of wordlist: 2315
mode:cheat

Guess #1
guessing> chart
Guess #1: chart
checking> gbbbg
Remaining Candidates: (4)
 covet:22
 clout:20
 count:19
 cleft:16
Guess #2
guessing> clout
Guess #2: clout
checking> gbyyg
Remaining Candidates: (1)
 count:25

• View Scoring

$ sort -hk 2 -t'=' scores.txt > sorted_scores.txt

Test solver against all words in dictionary

• Current usage

$ time ./solver --mode all 2>guess_nums_6.csv
Wordle Solver v4
mode:all

2294/2315=0.9909
done.

real    0m18.768s
user    0m17.029s
sys     0m1.063s

$ grep "success" guess_nums_6.csv | cut -d',' -f9 | awk 's+=$1{print s/NR}' | tail -n 1  # Average number of guesses
3.72113

• Fastest

$ time ./solver --mode all --multi 2>guess_nums_6.csv
Wordle Solver v4
mode:all
multi-threaded

done.

real    0m3.050s
user    0m18.391s
sys     0m1.671s

$ grep "success" guess_nums_6.csv | cut -d',' -f9 | awk 's+=$1{print s/NR}' | tail -n 1  # Average number of guesses
X.XXXXX

Best Results

Number of correct games over entire dictionary.

• v1.0: 98.14%

  • Average guesses on success: ??

• v2.0: 98.57%

  • Average guesses on success: 4.26687

• v3.0: 99.83%

  • Average guesses on success: 3.72113

• v4.0: 99.09%

  • Average guesses on success: 3.66696

Overview

There is a Checker and Solver. These two entities comprise the Wordle game. The Solver is the "player" while the Checker is the "referee."

Each Solver can be mixed and matched with any Selector.

Currently the best combo is TrieBasedWordleSolver & PositionalLetterWordleSelector.

Solvers

Role: Generate list of candidate words based on dictionary and results from prior guess.

• WordleSolver

  • Abstract Base Class. Interface for Solvers.

• WordlistWordleSolver

  • Abstract Base Class. Adds wordlist functionality.

• PassthroughWordleSolver

  • Intended for debugging Selectors. Does no processing of results.

• TrieBaseWordleSolver

  • Most powerful Solver. Uses a letter-based trie data structure to efficiently eliminate potential words based on results of prior guess.

Selectors

Role: Choose which word in a given list of words should be selected for the current Wordle guess.

• WordleSelector

  • Abstract Base Class. Interface for Selectors.

• RandomWordleSelector

  • From an iterable list of candidate words, chooses candidate randomly.

• EnhancedRandomWordleSelector

  • Randomly choose candidate words that contain more than one vowel and do not contain double letters.

• MostCommonLetterWordleSelector

  • Abstract Base Class. Interface for Selectors that want to compute frequency scores over remaining candidate words.

• NaiveMostCommonLetterWordleSelector

  • Basic approach to computing score based on most common letters in all remaining words.

• ImprovedMostCommonLetterWordleSelector

  • Improved approach that doesn't score letters that show up multiple times (they're less common) AND letters that are already green (no effect, but it stands to reason).

• PositionalLetterWordleSelector

  • Computes which letter is most common in each position. Scores each candidate word based on this and selects best candidate.

• FrequencyAndPositionalLetterWordleSelector

  • Blend of overall scoring (frequency) and positional letter scoring

Files

• answers.txt

  • Primitive 5-letter dictionary from the Internet

• answers_extended.txt

  • All allowed guesses, larger dictionary than answers.txt

• game_modes.[h|cpp]

  • Defines each game mode, defines the rules and orchestration of each game type

• guess_nums_6.csv

  • Results from current algorithm, 6 guesses allowed (default)

• guess_nums_7.csv

  • Results from current algorithm, 7 guesses allowed

• main.cpp

  • main() lives here, arg parsing

• wordle_buffer.h

  • Used for the multi-threaded solver scenario, collects all output then dumps when done

• wordle_checker.[h|cpp]

  • Automated checking against an answer

• wordle_checker_test.cpp

  • Tests for the checker

• wordle_helpers.h

  • Static plumbing to make user interaction easier

• wordle_rules.h

  • Basic game constraints defined here

• wordle_selectors.[h|cpp]

  • Selection Algorithms to feed to Solver

• wordle_solver.h

  • Abstract Base class/interface for the Solver

• wordle_trie.[h|cpp]

  • Trie data structure used for Wordle

• wordlist_wordle_solver.[h|cpp]

  • More intelligent Solvers that use a dictionary

ToDo

• Better/Additional dictionary - i.e. include allowed guesses dict

• Select strategy from cmd line

• Select mode from cmd line

• Measure success rates of various algos against whole dictionary

• Define richer exceptions and catch them in main to help in debugging

• Thread each parallel execution (Clang Mac doesn't support threading for loops :( )

• Break ties with more common letter in dictionary. TieBreaker class???? - mostly an unhit case

• Add aggressive easy mode Solver to knock out many letters with words not in remaining set. Likely to lead to 100% accuracy + lower average guesses.

• Implement hard mode Solver

• Implement hard mode verifier (experimental branch)

• Replace several size checks with NUM_LETTERS to consolidate understanding of what is tied to this global

• Raw pointers -> smart pointers (in progress, done?)

• Track lowest score of letter in word, sort on this somehow in getBestCandidate. Don't pick words with low lowest letter scores even if their score is the highest.

• How to optimize with easy (non-hard) mode guessing?

• Track biggest string of ties (ensure guess busts worst case scenarios, to help reach 100% solve rate)

• Wordle Cheat Mode, allow user to select a non-top choice and let algo run with that instead of the auto chosen word

• Make Selectors Composable (scoring, then selection should be done at another layer)

• Add wordle unicode decoder

• Add arg parsing OR multiple binaries

• Check guess against guess dict

• Support one output buffer per game, will help unlock multi-threaded game

Discussion

• Best Wordle guessing strategy(HN) https://slc.is/archive/best-wordle-strategy-explore-or-exploit/

• Wordle-Solver - solves 99.7% of common five-letter English words(HN) (github)

• Wordle-solving state of the art: all optimality results so far(HN) https://www.poirrier.ca/notes/wordle-optimal/

• https://botfights.ai/game/wordle

• https://codereview.stackexchange.com/questions/32817/multithreading-c-loop

• https://unicode-table.com/en/2B1B/

• Solving Wordle using information theory(YouTube)

Class Diagram

     WordleSolver
         ^
         |
   WordleSolverImpl
         ^
         |
  WordlistWordleSolver  --------------------------------->  WordleSelector
         ^                                                       ^
         |                                                       |
PassthroughWordleSolver                             PositionalLetterWordleSolver
         ^                                                       ^
         |                                                       |
TrieBasedWordleSolver -----> WordleTrie       FrequencyAndPositionalLetterWordleSelector


TrieBasedWordleSolver
|- WordleTrie*                                 (owns list of current correct answers)
|- FrequencyAndPositionalLetterWordleSelector* (owns behavior of selecting from a list of words)

Buffer Dependencies:

WordleTrie::makeXXGuess() main