14. 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)

            return "";

        String pre = strs[0]; //以数组第一个String作为基准

        for (int i = 1; i < strs.length; i++) {

            while (strs[i].indexOf(pre) != 0) //若后面的String不包括第一个String，把第一个String一步步从最后面裁减1

                pre = pre.substring(0, pre.length() - 1);  //pre的最后一个字符被裁了              

        }

        return pre;

    }

}