14.Longest Common Prefix

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.

class Solution(object):
    def longestCommonPrefix(self, strs):
        """
        :type strs: List[str]
        :rtype: str
        """
        if len(strs)==0 or '' in strs:
            return ''
        def judge(strs,i):
            temp = strs[0][i] if i<len(strs[0]) else False
            for p in strs:
                if i>=len(p):
                    return False
                if p[i]!=temp:
                    return False
            return True
        res = ''
        i = 0
        while judge(strs,i):
            res += strs[0][i]
            i += 1
        return res