The problem is to find “word paths”. What this means is that you find a path from one word to another word, changing one letter each step, and each intermediate word must be in the dictionary.
We tend to use the dictionary file on a linux in /usr/share/dict/words.
Some example solutions:
rial -> real -> feal -> foal -> foul -> foud
yagi > yali > pali > palp > paup -> plup -> blup
jina -> pina -> pint -> pent -> peat -> prat -> pray
fike -> fire -> fare -> care -> carp -> camp
The program should take as input the path to the word file, any start word and an end word and print out at least one path from start to end, or something indicating there is no possible path if appropriate. e.g.
$ python ./wordpaths.py /usr/share/dict/words cat dog
cat -> cag -> cog -> dog