11.5---含有空字符串的字符串查找（CC150）

import java.util.*;

public class Finder {
   public static int findString(String[] a,int n, String key){
        int left = 0;
        int right = a.length - 1;
        while(left <= right){
            int mid = (left + right) / 2;
            
            while(mid < right && a[mid] == ""  ){
                mid++;
            }
            while(mid > left && a[mid] == "") {
                mid--;
            }
            
            if(key.equals(a[mid])) return mid;

        //else if(key.compareTo(a[mid]) == -1){
            else if(key.compareTo(a[mid]) < 0){
                right = mid -1;
            }
            else {
                left = mid + 1;
            }
        }

        return -1;
    }
}