longest_common_prefix

class Solution:
    """
    @param strs: A list of strings
    @return: The longest common prefix
    """
    def longestCommonPrefix(self, strs):
        # write your code here
        if len(strs)==0:
            return ""
        for prefix in range(len(strs[0])):
            mark = strs[0][prefix]
            for word in strs[1:]:
                if prefix < len(word):
                    if word[prefix] != mark:
                        return strs[0][:prefix]
                else:
                    return strs[0][:prefix]
        return strs[0]