LeetCode OJ 之 Longest Common Prefix

题目：Write a function to find the longest common prefix string amongst an array of strings.
分析：典型题目。LCP问题，即找出字符串数组中最大公共前缀。思路为先找出前两个字符串的公共前缀，再找出该公共前缀与下一个字符串的公共前缀，以此类推，直到找出所有字符串的公共前缀。程序如下：

public class Solution {
    public String longestCommonPrefix(String[] strs) {
        int arrlen = strs.length;
        String result = new String();
        if(arrlen == 0){
            return result;
        }
        result = strs[0];
        for(int i = 1; i < arrlen; i++){
            result = findCommonPrefix(result,strs[i]);
        }
        return result;
    }

    public String findCommonPrefix(String str1,String str2){
        char[] charr1 = str1.toCharArray();
        char[] charr2 = str2.toCharArray();
        StringBuilder resultsb = new StringBuilder();
        int i = 0;
        int str1len = str1.length();
        int str2len = str2.length();
        while(i < str1len && i < str2len && charr1[i] == charr2[i]){
            i++;
        }
        for(int j = 0; j < i; j++){
            resultsb.append(charr1[j]);
        }
        return resultsb.toString();
    }
}