grantslatton
/ fizzbuzz.c
Last active
August 19, 2022 11:20
FizzBuzz solved using only bit twiddling. It essentially uses two deterministic finite automata for divisibility testing.
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| #include <stdio.h> | |
| int f0(unsigned int x) { return x? (x&(1<<31)? f1(x<<1) : f0(x<<1)) : 1; } | |
| int f1(unsigned int x) { return x? (x&(1<<31)? f3(x<<1) : f2(x<<1)) : 0; } | |
| int f2(unsigned int x) { return x? (x&(1<<31)? f0(x<<1) : f4(x<<1)) : 0; } | |
| int f3(unsigned int x) { return x? (x&(1<<31)? f2(x<<1) : f1(x<<1)) : 0; } | |
| int f4(unsigned int x) { return x? (x&(1<<31)? f4(x<<1) : f3(x<<1)) : 0; } | |
| int t0(unsigned int x) { return x? (x&(1<<31)? t1(x<<1) : t0(x<<1)) : 1; } | |
| int t1(unsigned int x) { return x? (x&(1<<31)? t0(x<<1) : t2(x<<1)) : 0; } | |
| int t2(unsigned int x) { return x? (x&(1<<31)? t2(x<<1) : t1(x<<1)) : 0; } |