1 #include <omp.h>
  2 #include <stdio.h>
  3 #include <stdlib.h>
  4
  5 int main()
  6 {
  7   int n=4, threads=2;
  8   int *p;
  9   int **r;
 10   int m = threads-1;
 11   int k;
 12
 13   int a[] = {2, 6, 3, 8};
 14   p = malloc(n * sizeof(int));
 15   r = (int **)malloc((2*n-1) * sizeof(int*));
 16   int i, j;
 17   for(i=0; i<(2*n-1); ++i)
 18     r[i] = malloc(n * sizeof(int));
 19
 20 #pragma omp parallel for num_threads(threads)
 21   for(i=0;i<n;++i)
 22   {
 23 #pragma omp parallel for num_threads(threads)
 24     for(j=0;j<n;++j)
 25     {
 26         if(a[i]<a[j])
 27           r[i+n-1][j] = 1;
 28         else
 29           r[i+n-1][j] = 0;
 30     }
 31   }
 32
 33 #pragma omp parallel for num_threads(threads)
 34   for(j=0;j<n;++j)
 35   {
 36     for(k=m-1;k>=0;--k)
 37 #pragma omp parallel for num_threads(threads)
 38       for(i=1<<k;i<1<<(k+1);++i)
 39         r[j][i] = r[j][2*i] + r[j][2*i+1];
 40
 41     p[j] = r[0][j];
 42   }
 43 #pragma omp parallel for num_threads(threads)
 44   for(j=0;j<n;++j)
 45   {
 46     a[p[j]] = a[j];