Play on Words
Some of the secret doors contain a very interesting word puzzle. The team of archaeologists has to solve it to open that doors. Because there is no other way to open the doors, the puzzle is very important for us.
There is a large number of magnetic plates on every door. Every plate has one word written on it. The plates must be arranged into a sequence in such a way that every word begins with the same letter as the previous word ends. For example, the word ``acm'' can be followed by the word ``motorola''. Your task is to write a computer program that will read the list of words and determine whether it is possible to arrange all of the plates in a sequence (according to the given rule) and consequently to open the door.
a' through '
z' will appear in the word. The same word may appear several times in the list.
If there exists such an ordering of plates, your program should print the sentence "
Ordering is possible.". Otherwise, output the sentence "
The door cannot be opened.".
3 2 acm ibm 3 acm malform mouse 2 ok ok
The door cannot be opened. Ordering is possible. The door cannot be opened.