parallel1.c

/*
* A small college is thinking of instituting a six-digit student ID
* number. It wants to know how many "acceptable" ID numbers there
* are. An ID number is "acceptable" if it has no two consecutive
* identical digits and the sum of the digits is not 7, 11, or 13. *
* 024332 is not acceptable because of the repeated 3s.
* 204124 is not acceptable because the digits add up to 13.
* 304530 is acceptable.
*/
/*
* Function "no_problem_with_digits" extracts the digits from * the ID number from right to left, making sure that there are * no repeated digits and that the sum of the digits is not 7,
* 11, or 13.
*/
#include <stdio.h>
#include <omp.h>

#define NUM_THREADS 1

int no_problem_with_digits (int i)
{
  int j;
  int latest; /* Digit currently being examined */
  int prior; /* Digit to the right of "latest" */
  int sum; /* Sum of the digits */
  prior = -1;
  sum = 0;
  for (j = 0; j < 6; j++) {
    latest = i % 10;
    if (latest == prior)
      return 0;
    sum += latest;
    prior = latest;
    i /= 10;
  }
  if ((sum == 7) || (sum == 11) || (sum == 13))
    return 0;
  return 1;
}
/*
* Function "main" iterates through all possible six-digit ID
* numbers (integers from 0 to 999999), counting the ones that * meet the college's definition of "acceptable."
*/
int main (void)
{
  int count; /* Count of acceptable ID numbers */
  int i=0;
  double start_time = omp_get_wtime();
  omp_set_num_threads(NUM_THREADS); //define el numero de hilos


    int nth = omp_get_num_threads();
    count = 0;
    #pragma omp parallel for
      for (i = 0; i< 1000000; i++){
        #pragma omp critical
        if (no_problem_with_digits(i)) {
          count++;
        }
      }
  printf("There are %d acceptable ID numbers\n", count);
  printf("Time: \t %f \n", omp_get_wtime()-start_time);
  return 0;
}