My priorities: the programs should be

1. understandable and verifiable (the highest priority);
2. portable;
3. fast.

• Dynamic allocation of main memory (farmalloc, farrealloc, ... ) is substituted by static arrays (each kept within 64 Kbytes).
• Macros max, min are defined explicitly.
• Long integer division ldiv and the corresponding data type ldiv_t are substituted by straighforward use of x/y and x%y.

Each line of each data file is enclosed in square brackets [...], which makes the programs insensitive to a specific representation for end-of-line (NL, or CR, or CR+NL, ...).

Texts of programs are now mosaic: some lines are by Y. Rosenberg, others are mine. Sometimes it makes the code somewhat unnatural and simplifiable.

The first program prepare is completely mine. It is not necessary, but I find it convenient.

The second program searh is mostly by Y. Rosenberg, but spoiled by me: I have removed a speeding-up mechanism ("Letter 2 table"). Why did I? In order to make the program more understandable. True, it runs much slower, but still, the most time-consuming step is distance, not search.

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Programmer's notes