I'm making algorithm like crossword,

but i dont know how to design d algorith.

for example,

there are words like 'car', 'apple' in the dictionary.

and the 'app' words is given on the board.

and there are letters like 'l' 'e' 'c' 'r'....for making words.

so the algorithm work is making correct words which are stored in dictionary.

app -> lapp-> leapp-> lecapp-> .... -> lappe -> eappc -> ... -> appl -> apple(correct answer)

what is the best solution for this algorithm?