CC150

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);
    }

}