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Problem D
Catenyms
Time Limit: 1000ms
Memory Limit: 65536kb Description
A catenym is a pair of words separated by a period such that the last letter of
the first word is the same as the last letter of the second. For example, the
following are catenyms:
dog.gopher gopher.rat rat.tiger aloha.aloha arachnid.dogA compound catenym is a sequence of three or more words separated by periods such that each adjacent pair of words forms a catenym. For example, aloha.aloha.arachnid.dog.gopher.rat.tigerGiven a dictionary of lower case words, you are to find a compound catenym that contains each of the words exactly once. Input
The first line of standard input
contains t, the number of test cases. Each test case begins with
3 <= n <= 1000 - the number of words in the dictionary. n
distinct dictionary words follow; each word is a string of between 1 and 20
lowercase letters on a line by itself.
Output
For each test case, output a line
giving the lexicographically least compound catenym that contains
each dictionary word exactly once. Output "***" if there is no solution.
Sample Input
2 6 aloha arachnid dog gopher rat tiger 3 oak maple elm Sample Output
aloha.arachnid.dog.gopher.rat.tiger *** |