
ZOJ Problem Set  2349
In this problem, you are given a list of words (sequence of lower case letters). From this list, find the longest chain of words w_{1}, ..., w_{n} such that w_{i} is a mixed extension of w_{i1}. A word A is a mixed extension of another word B if A can be formed by adding one letter to B and permuting the result. For example, "ab", "bar", "crab", "cobra", and "carbon" form a chain of length 5. This problem contains multiple test cases! The first line of a multiple input is an integer N, then a blank line followed by N input blocks. Each input block is in the format indicated in the problem description. There is a blank line between input blocks. The output format consists of N output blocks. There is a blank line between output blocks. Input Each input block contains at least two, but no more than 10000 lines. Each line contains a word. The length of each word is at least 1 and no more than 20. All words in the input are distinct. Output Write the longest chain that can be constructed from the given words. Output each word in the chain on a separate line, starting from the first one. If there are multiple longest chains, any longest chain is acceptable. Sample Input
1 Sample Output
ab Source: Rocky Mountain 2004 