Hint

If your program finds a superset of the encodings shown in z1000.out, you have probably met the following pitfall.
Many people first misunderstand the requirements with respect to the insertion of digits as follows. They insert a digit even if they have inserted a word at some point, but could then not complete the encoding up to the end of the phone number. That is, they use backtracking.
This is incorrect. Encodings must be built step-by-step stricly from left to right; the decision whether to insert a digit or not is made at some point and, once made, must never be changed.

Sorry for the confusion. The original test had this ambiguity and to be able to compare the new work times with the old ones, the spec must remain as is. If you ran into this problem, please report the time you spent finding and repairing; put the number of minutes in the 'special events' section of the program header comment. Thanks a lot!

Lutz Prechelt, prechelt@ira.uka.de, Last modified: Fri Nov 19 17:34:00 MET 1999