Array rearranging algorithm

/*Suppose we have an array a1, a2, ..., an, b1, b2, ..., bn. Implement an algorithm to change

this array to a1, b1, a2, b2, ..., an, bn.*/
a1, b1   ok

a1, a2, b1, b2-> a1, a2<->b1, b2-> a1, b1, a2, b2 ok

a1,a2,a3,a4,b1,b2,b3,b4 -> a1 a2 (b1 b2), (a3,a4), b3, b4-> it becomes 2 subproblems of the above



//size of arr_num must be even number

void rearrange(int arr_num[], int p, int q)

{



if ( p == q || g == p+1) return;

int r = (q+p)/2;



//Exchange: (p+r)/2........r<----> r+1......(r+q)/2

for(int i = (p+r)/2; i

{

int temp= arr_num[i];

arr_num[i]=arr_num[r+1+i];

arr_num[r-1+i] = temp;

};



rearrange(arr_num, p, r);

rearrange(arr_num, r+1, q);

return;



}