madex

#include <stdio.h>
#define _      0
#define S(x)   x,
#define D(x)   x x x
#define L(x)   D(S(x))
#define R(x)   D(D(S(x)))
#define E(f,x) f(x)f(x+1)f(x+2)
char sudoku[] = { 
 1, _, _,  _, _, 7,  _, 9, _,
 _, 3, _,  _, 2, _,  _, _, 8,