14. Longest Common Prefix

https://leetcode.com/problems/longest-common-prefix/description/

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.

Solution:

class Solution(object):
    def longestCommonPrefix(self, strs):
        """
        :type strs: List[str]
        :rtype: str
        """
        ret = ''
        if len(strs) == 0:
            return ret
        for ssi in range(len(strs[0])):
            ss = strs[0][ssi]
            for i in range(1, len(strs), 1):
                if ssi > len(strs[i])-1 or ss != strs[i][ssi]:
                    return ret
            ret += strs[0][ssi]
        return ret