最长公共前缀

题目：最长公共前缀

要求：编写一个函数来查找字符串数组中的最长公共前缀。如果不存在公共前缀，返回空字符串 ""。

例如 ：
输入：["flower","flow","flight"]		["dog","racecar","car"]
输出："fl"     ""

题解代码如下：

class Solution {
    private String longestCommonPrefix(String[] strs) {
        if (null == strs || strs.length == 0) {
            return "";
        }
        String longestCommonPrefix = strs[0];
        for (int i = 1; i < strs.length; i++) {
            int index = 0;
            String cur = strs[i];
            for (int j = 0; j < longestCommonPrefix.length(); j++) {
                if (j < cur.length() && longestCommonPrefix.charAt(j) == cur.charAt(j)) {
                    index++;
                } else {
                    longestCommonPrefix = longestCommonPrefix.substring(0, index);
                    break;
                }
            }
        }
        return longestCommonPrefix;
    }
}

我的题解有点复杂化了，看看下面这个吧

class Solution {
    private String longestCommonPrefix(String[] strs) {
        if (strs == null || strs.length == 0){
            return "";
        }
        String reg = strs[0];
        for (String str : strs) {
            while (!str.startsWith(reg)) {
                if (reg.length() == 1) {
                    return "";
                }
                reg = reg.substring(0, reg.length() - 1);
            }
        }
        return reg;
    }
}