帮忙看一下，string concatenation

[cross2]

问题如下：

String concatenation
Write a program that will accept two strings (1 <= length <= 50) and output the sequence of the first string converting to the second string, such that each conversion only add/modify/delete one character. In case more than one such conversion sequence is possible, print the one sequence that contains the shortest steps.

Input specification:
Two strings separated by space on a single line.

Output Specification:
The sequence of conversion steps, each in a separate line.

Examples:

Input:
abcd afgd

Output:
abcd
afcd
afgd

Input:
efgh cdef

Output:
efgh
efg
ef
def
cdef

Input:
abcdefg bdf

Output:
abcdefg
bcdefg
bdefg
bdfg
bdf


希望高手提供个思路，谢谢。

[jakqigle]

ACM啊？lz新手吧？

[cross2]

>>ACM啊？lz新手吧？

学校的作业，但是一点头绪也没有。帮忙看看吧，应该如何入手呢？

[jakqigle]

简单想的话，对于第一个串与第二个比较匹配，匹配相同的串不动，其余不匹配的串再通过加减删除使第一个string向第二个转换。