14. Longest Common Prefix

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

求多个字符串的最长公共前缀。

public class Solution {  
  
    public String longestCommonPrefix(String[] strs) {  
        if (strs.length == 0)  
            return "";  
        for (int i = 0; i < strs[0].length(); i++) {  
            for (int j = 1; j < strs.length; j++)  
                if (strs[j].length() <= i || strs[j].charAt(i) != strs[0].charAt(i))  
                    return strs[0].substring(0, i);  
        }  
        return strs[0];  
    }  
}  

1、当strs为空，直接输出“”

2、当strs中含有“”，直接输出“”

3、strs[0]的最长长度由最短公共长度l决定（code line：15）

class Solution:
    # @return a string
    def longestCommonPrefix(self, strs):
        if strs == []:
            return ""
        for i in range(1,len(strs)):
            l1 = len(strs[0])
            l2 = len(strs[i])
            if l1>l2:
                l = l2
            else:
                l = l1
            if l==0:
                return ""
            strs[0]=strs[0][0:l]
            for j in range(l):
                if strs[0][j] != strs[i][j]:
                    strs[0] = strs[0][0:j]
                    break
        return strs[0]