#include<stdio.h>

int main(){2k  when k∈ [0, n/2)
  int sample[12] = {1,3,5,7,9,11,2,4,6,8,10,12};
  int n = sizeof(sample)/sizeof(int);
  int i=0;
  int k=1;
  int temp;
  do
    {
       if(k<n/2){
       temp = sample[1];
       sample[1]= sample[2*k];
       sample[2*k] = temp;
       k = 2*k;
       }
       else{
        temp = sample[1];
        sample[1] = sample[2*k - n + 1];
        sample[2*k - n + 1] = temp;
        k = 2*k - n + 1;
       }
   }while(k!=1);

  for(i=0;i<n;i++)
     printf("%d",sample[i]);
  printf("\n");
  return 0;
}

#include <cstdlib>
#include <iostream>

using namespace std;

void trans(int* x, int n){
  for(int i=1; i<n; ++i)
    for(int j=0; j<i; ++j)
      std::swap(x[n-i+2*j],x[n-i+2*j+1]);
}

void print_list(int* x, int n){
  for(int i=0; i<n; ++i)
    std::cout<<x[i]<<",";
  std::cout<<"\n";
}
int main(int argc, char *argv[])
{
  int a[]={1,3,5,7,9,2,4,6,8,10};
  print_list(a, sizeof(a)/sizeof(int));
  trans(a, sizeof(a)/sizeof(int)/2);
  print_list(a, sizeof(a)/sizeof(int));
}