leetcode Longest Common Prefix 多个字符串的最长字串

 public class Solution {
     public String get(String a,String b)
     {

         if(a==""||b=="") return "";
         int len1=a.length();
         int len2=b.length();
         int len=len1;
         if(len>=len2) len=len2;
         String s="";
         for(int i=0;i<len;i++)
         {
             if(a.charAt(i)==b.charAt(i))
             {
                 s+=a.charAt(i);
             }
             else break;

         }
         return s;
     }

     public String longestCommonPrefix(String[] strs) {
         int len=strs.length;
         if(len==0) return "";
         if(len==1) return strs[0];
         String ans=get(strs[0],strs[1]);
         if(ans=="") return "";
         else
         {
             for(String s:strs)
             {
                 ans=get(s,ans);
                 if(ans=="") return "";
             }

         }
         return ans;

     }
 }