if(array==null)
       {
           return 0;
       }
       int begin = 0;
       int end = array.length-1;
       int mid = begin + (end-begin)/2;
       int count=0;
       while(begin<=end)
       {
           if(array[mid]==k)
           {
                count++;
                int t=mid-1;
                int n=mid+1;
                while(t>=0&&array[t]==k)
                {
                    t--;
                    count++;
                }
                while(n<=array.length-1&&array[n]==k)
                {
                    count++;
                    n++;
                }
                return count;
           }
           else if(array[mid]<k)
           {
                begin=mid+1;
                mid = begin + (end-begin)/2;
           }
           else{
                end = mid-1;
                mid = begin + (end-begin)/2;
           }

       }
       return 0;