【LeetCode算法-14】Longest Common Prefix

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

If there is no common prefix, return an empty string "".

Example 1:

Input: ["flower","flow","flight"]
Output: "fl"

Example 2:

Input: ["dog","racecar","car"]
Output: ""
Explanation: There is no common prefix among the input strings.

Note:

All given inputs are in lowercase letters a-z.

思路：

根据第一个字符串，不断去循环判断后面的字符串

代码：

class Solution {
    public String longestCommonPrefix(String[] strs) {
        if(null == strs || strs.length == 0){
            return "";
        }else if(strs.length == 1){
            return strs[0];
        }
        String result = "";
        for(int i = 1;i<=strs[0].length();i++){
            String prefix = strs[0].substring(0,i);
            for(int j=1;j<strs.length;j++){
                if(strs[j].startsWith(prefix)){
                    if(j==strs.length-1){
                        result = prefix;
                    }
                }else{
                    break;
                }
            }
        }
        return result;
    }
}

String.substring（0，x）,第二个参数很神奇，x就算超过字符串的长度也没关系，所以不用担心数组越界问题