Consider the problem of mapping golf score names to their numeric values as succinctly as possible. The complete mapping is as follows:
| Score Name | Numerical value |
|---|---|
| Condor | -4 |
| Albatross | -3 |
| Eagle | -2 |
| Birdie | -1 |
| Par | 0 |
| Bogey | 1 |
| Double Bogey | 2 |
| Triple Bogey | 3 |
In Python 2 we could use a magic formula like hash(s+"V*? ")%9-4 (64-bit Python) or hash(s+"N.H.")%9-4 (32-bit Python).
This program finds such magic strings using brute force.
To specify a problem you have to edit the file config.h.
MAGIC_LEN determines the length of the magic string.
MAGIC_MIN and MAGIC_MAX determine the range of allowed characters in the magic string (end points included).
Use typedef int64_t pyint; for 64-bit Python and typedef int32_t pyint; for 32-bit Python.
MODULUS determines the modulus used in the magic formula.
This value should almost always be odd.
PAIRS is the table of the desired input / output pairs.
$ gcc -O3 prefixcruncher.c -o prefixcruncher.out
$ ./prefixcruncher.out
56 2a 3f 20 V*?