wordtransformation游戏

wordtransformation就是看一个word能不能每次只变化一个字母，通过k次，转变成另一个word，例如full-foll-fool,full就通过三步转为fool，输入一个word，输出转化的步骤-Let us consider the following puzzle called a word ladder. Transform the word “FOOL” into the

word “SAGE”. In a word ladder puzzle you must make the change occur gradually by changing

one letter at a time. At each step you must transform one word into another word, you are not

allowed to transform a word into a non-word. The word ladder puzzle was invented in 1878 by

Lewis Carroll, the author of Alice in Wonderland. The following sequence of words shows one

possible solution to the problem posed above.