(java)leetcode Longest Common Prefix

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

思路1:本题是要找一个字符串数组的最长公共前缀。

首先求出最短字符串的长度，然后从0到最短字符串长度遍历每个字符串，找到最长的公共前缀

代码如下(已通过leetcode)

public class Solution {
public String longestCommonPrefix(String[] strs) {
String str = "";
int lengthsize = strs.length;
if (strs == null)
return null;
if (lengthsize == 0)
return str;
if (lengthsize == 1)
return strs[0];
int limitlength = strs[0].length();
boolean flag = true;
for (int i = 1; i < lengthsize; i++) {
if (strs[i].length() < limitlength)
limitlength = strs[i].length();
}
for (int j = 0; j < limitlength; j++) {


for (int k = 1; k < lengthsize; k++) {
if (strs[k].charAt(j) != strs[0].charAt(j)) {
flag = false;
break;
}


}
if (flag == false)
break;
//System.out.println(j);
str += strs[0].charAt(j);


}
return str;
}
}