Thanks , i tried to implement your idea .

 public static String fairRations(List<Integer> B) {
Integer pub[]= new Integer [B.size()];
pub=B.toArray(pub);
int count_odd=0,count=0,l=-1,r=-1;

for(int i=0;i<pub.length;i++)
{
    if(pub[i]%2!=0)
    count_odd++;;


}
if(count_odd%2!=0)
return "NO";
else
 {
   for(int i=0;i<pub.length;i++)
   {
       if(pub[i]%2!=0)
       {
         if(l==-1 )
         {
             l=i;
         }
         else if(l!=-1 && r==-1)
         {
             r=i;
         }
         if(l!=-1 && r!=-1)
         {
             count+=(r-l);

             l=-1;
             r=-1;
         } 
       }
   }
}
count*=2;

return count+"";

}