题目描述

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.

AC代码

借鉴自 leetcode

class Solution {
   public String longestCommonPrefix(String[] strs) {
    if(strs == null || strs.length == 0)    return "";
    String pre = strs[0];
    int i = 1;
    while(i < strs.length){
        while(strs[i].indexOf(pre) != 0)  // 返回指定子字符串在此字符串中第一次出现处的索引。如果不存在，则返回-1；
            pre = pre.substring(0,pre.length()-1);
        i++;
    }
    return pre;
}
}