CC150 - 11.5

Question:

Given a sorted array of strings which is interspersed with empty strings, write a method to find the location of a given string. 

 package POJ;

 public class Main {

     /**
      *
      * 11.5 Given a sorted array of strings which is interspersed with empty
      * strings, write a method to find the location of a given string.
      *
      */
     public static void main(String[] args) {
         Main so = new Main();
     }

     public int search(String[] strs, String str) {
         if (strs == null || str == null || str.equals("")) {
             return -1;
         }
         return searchR(strs, str, 0, str.length() - 1);
     }

     private int searchR(String[] strs, String str, int first, int last) {
         // TODO Auto-generated method stub
         if (last < first)
             return -1;
         int mid = (first + last) / 2;
         if (strs[mid].isEmpty()) {
             int left = mid - 1;
             int right = mid + 1;
             while (true) {
                 if (left < first && right > last)
                     return -1;
                 else if (right <= last && !strs[right].isEmpty()) {
                     mid = right;
                     break;
                 } else if (left >= first && !strs[left].isEmpty()) {
                     mid = left;
                     break;
                 }
                 right++;
                 left--;
             }
         }
         if (str.equals(strs[mid]))
             return mid;
         else if (strs[mid].compareTo(str) < 0)
             return searchR(strs, str, mid + 1, last);
         else
             return searchR(strs, str, first, mid - 1);
     }

 }