we have an array of 2n elements like "a1 a2...an b1 b2...bn". WAP to rearrange the array as "a1 b1 a2 b2...an bn" time complexity is O(n) no extra RAM

#include
#define SWAP(a,b) a^=b^=a^=b

int string[100];
int m;

void Replace(int n,int start){
int i,j;
for(i=start,j=0;j {
SWAP(string[i],string[n+i]);
}
n=n-1;
if(n>0)
Replace(n,start+1);
}

main()
{
int i;
printf("Enter no of elements (max 100): ");
scanf("%d",&m);
if(m%2){
printf("odd nos\n");
}
else{
printf("Enter numbers: ");
for(i=0;i scanf("%d",&string[i]);
for(i=0;i printf("%d\t",string[i]);
printf("\n");

Replace(m/2-1,1);
for(i=0;i printf("%d\t",string[i]);
printf("\n");
}
}