#define ABS(x)           ((x) >= 0 ? (x) : -(x))
#define ABSDIF(x, y)     ((x) >= (y)  ? (x)-(y) : (y)-(x))
#define ABSMAIOR(x, y)   ((x) >  (y) || (x) <  -(y))
#define MAX(x, y)        ((x) >=  (y)? (x) : (y))
#define MIN(x, y)        ((x) <=  (y)? (x) : (y))
#define LIM(x, y, z)     ((y) < (x) ? (x) : (y) > (z) ? (z) : (y))
#define SINAL(x)         ((x) > 0 ? 1 : (x) < 0 ? -1 : 0)
/* ou
#define SINAL(x)         (((x) > 0) - ((x) < 0))
*/
#define TROCA(x, y, aux) ((aux) = (x), (x) = (y), (y) = (aux))