#
# 代码中的类名、方法名、参数名已经指定,请勿修改,直接返回方法规定的值即可
#
# 
# @param strs string字符串一维数组 
# @return string字符串
#
class Solution:
    def longestCommonPrefix(self , strs: List[str]) -> str:
        # write code here
        if strs == []:
            return ""
        prefix = strs[0]
        for s in strs[1:]:
            i = 0 
            while i < len(prefix) and i < len(s) and prefix[i] == s[i]:
                i += 1 # 下一个字符位置
            prefix = prefix[:i]
        if not prefix:
            return ""
        return prefix