14. Longest Common Prefix

 1 class Solution {
 2     
 3     private int Minlen(String[] str)
 4     {
 5         int min = Integer.MAX_VALUE;
 6         
 7         for(int i=0;i<str.length;i++)
 8         {
 9             min = Math.min(min,str[i].length());
10         }
11         return min;
12         
13     }
14     public String longestCommonPrefix(String[] strs) {
15         
16         if(strs ==null || strs.length==0)
17             return "";
18         
19         int len = Minlen(strs);
20         StringBuilder res = new StringBuilder();
21         int index =0;
22         
23         while(index<len)//数组中的每个字符串
24         {
25             for(int i=1;i<strs.length;i++)
26             {
27                 if(strs[i].charAt(index)!=strs[0].charAt(index))
28                     return res.toString();
29             }
30             res.append(strs[0].charAt(index));
31             index++;
32         }
33         return res.toString();
34         
35         
36         
37     }
38 }