River crossing Puzzle 2

 渡河問題2 (statement)，Problem via 許元銘

結果視覺化

Visualization to verify 

ChatGPT 5 works 4/5.  (Three claimed to use Python code execution. Therefore, is it true code was generated and then executed?) 

*1 Reasoning, 

2 BFS x, validator,  BFS*

*3 Reasoning,

*4 BFS, validate, viz,

*5 BFS

Code Gen

Use ChatGPT 5 to generate BFS search

 search that works

Use Claude to generate A*

 it takes 15 steps. (thanks to the python code generated by Claude)

python code

another 15-step solution

yet another 15-step

one more 15-step

last 15-step