Longest Common Prefix

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

class Solution {    public String longestCommonPrefix(String[] strs) {        if(strs.length==0)//要注意字符串数组越界的判断            return "";        String prefix=strs[0];        for(int i=1;i<strs.length;i++){            while(strs[i].indexOf(prefix)!=0){//记住indexOf()方法的使用。                prefix=prefix.substring(0,prefix.length()-1);            }        }        return prefix;    }}