Random.h

#ifndef RANDOM_H
#define RANDOM_H
#include "Setting.h"
#include <cstdlib>
 
// the random seeds for all threads.
unsigned long long *next_random;
 
// reset the random seeds for all threads
extern "C" void randReset() {
  next_random =
      (unsigned long long *)calloc(workThreads, sizeof(unsigned long long));
  for (INT i = 0; i < workThreads; i++)
    next_random[i] = rand();
}
 
// get a random interger for the id-th thread with the corresponding random
// seed.
unsigned long long randd(INT id) {
  next_random[id] = next_random[id] * (unsigned long long)(25214903917) + 11;
  return next_random[id];
}
 
// get a random interger from the range [0,x) for the id-th thread.
INT rand_max(INT id, INT x) {
  INT res = randd(id) % x;
  while (res < 0)
    res += x;
  return res;
}
 
// get a random interger from the range [a,b) for the id-th thread.
INT rand(INT a, INT b) { return (rand() % (b - a)) + a; }
#endif