Bitonic Sort

#include<bits/stdc++.h>
using namespace std;
 
void compAndSwap(int a[], int i, int j, int dir)
{
    if (dir==(a[i]>a[j]))
        swap(a[i],a[j]);
}
 
void bitonicMerge(int a[], int low, int cnt, int dir)
{
    if (cnt>1)
    {
        int k = cnt/2;
        for (int i=low; i<low+k; i++)
            compAndSwap(a, i, i+k, dir);
        bitonicMerge(a, low, k, dir);
        bitonicMerge(a, low+k, k, dir);
    }
}

void bitonicSort(int a[],int low, int cnt, int dir)
{
    if (cnt>1)
    {
        int k = cnt/2;
 
        // sort in ascending order since dir here is 1
        bitonicSort(a, low, k, 1);
 
        // sort in descending order since dir here is 0
        bitonicSort(a, low+k, k, 0);
 
        // Will merge whole sequence in ascending order
        // since dir=1.
        bitonicMerge(a,low, cnt, dir);
    }
}
 
void sort(int a[], int N, int up)
{
    bitonicSort(a,0, N, up);
}
 
// Driver code
int main()
{
    int a[]= {3, 7, 4, 8, 6, 2, 1, 5};
    int N = sizeof(a)/sizeof(a[0]);
 
    int up = 1;   // means sort in ascending order
    sort(a, N, up);
 
    printf("Sorted array: \n");
    for (int i=0; i<N; i++)
        printf("%d ", a[i]);
    return 0;
}