#include <stdio.h>
#include <omp.h>
#define TOTAL 2000000   //gcc -fopenmp tp4.c -o tp4   ./tp4
// gcc -fopenmp tp4.c -o tp4
// OMP_NUM_THREADS=4 ./tp4
//for np in 1 2 4 8 16; do OMP_NUM_THREADS=$np ./syracuse;done

int main(int argc, char * argv [])
{
    int pass=0, cur;
   double start = omp_get_wtime();
//sol 1
#pragma omp parallel for reduction (+:pass)
        for(int i=0; i<TOTAL; i++) {
            cur=i;
            while (cur>1)
            {
                cur=cur%2?3*cur+1:cur/2;
            }
        pass++;
        }
// sol 2
#pragma omp parallel for private (cur)
        for(int i=0; i<TOTAL; i++) {
            cur=i;
            while (cur>1)
            {
                cur=cur%2?3*cur+1:cur/2;
            }
#pragma omp critical
        pass++;
        }
//sol3
    #pragma omp paralel
    {
        int mypass=0,cur;
    #pragma omp for
        for(int i=0; i<TOTAL; i++) {
            cur=i;
            while (cur>1)
            {
                cur=cur%2?3*cur+1:cur/2;
            }
            mypass++;
        }
        
#pragma omp critical
        pass=pass+mypass;
    }

// sol 4
#pragma omp parallel
{
    int id= omp_get_thread_num();
    int np = omp_get_num_threads();
    int cur;
    for(int i=id; i<TOTAL; i=i+np) {
        cur=i;
        while (cur>1)
        {
            cur=cur%2?3*cur+1:cur/2;
        }
#pragma omp critical
        pass++;
    }
}
    
///////////////////// MODIFIER JUSQU'ICI UNIQUEMENT /////////////////////
   double end = omp_get_wtime();
   printf("%d out of %d ! (delta= %d)\n", pass, TOTAL, TOTAL-pass);
   printf("time: %lf ms\n ", (end-start)*1000);

}