最长公共前缀

SubString is important !!!

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

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

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

我写不出来（0 ms）

class Solution {
 public static String longestCommonPrefix(String[] strs) {
    int count = strs.length;
    String prefix = "";
    if(count != 0){
        prefix = strs[0];
    }
    for(int i=0; i<count; i++){
        while(!strs[i].startsWith(prefix)){
            prefix = prefix.substring(0, prefix.length()-1);
        }
    }
    return prefix;
}
}

这题真是一波三折，因为之前做过最长前缀字符串的相关问题，我本来准备打算做XOR，但是发现字符串不能做XOR，我就想先把字符串转成数字，然后再用数字XOR再转回字符串，然后发现数字并不能转回字符串，数字只能转回数字字符！然后我就用普通方法试了一下，结果失败了几次以后心态崩了，就不高兴写了_(:з」∠)_

关键代码在于不断对比字符串，减少字符数量，直到startsWith()返回true。

字符串部分的算法就到此结束了。