题目：Write a function to find the longest common prefix string amongst an array of strings.

public class Solution {
    public String longestCommonPrefix(String[] strs) {
        if(strs.length<=0)
            return "";
       
        for(int i=0;i<strs[0].length();i++)
         { 
            char x = strs[0].charAt(i);
           
            for(int j=1;j<strs.length;j++)
              if(i==strs[j].length()||strs[j].charAt(i) != x)
                {
                    System.out.println(strs[0].substring(0,i));
                    return strs[0].substring(0,i);
                }
            
         }
        return strs[0];
    }
}