@author: ZZQ

@software: PyCharm

@file: longestCommonPrefix.py

@time: 2018/9/16 17:50

要求：查找字符串数组中的最长公共前缀。如果不存在公共前缀，返回空字符串 ""

e.g.： 输入: ["flower","flow","flight"] 输出: "fl"

输入: ["dog","racecar","car"] 输出: "" 解释: 输入不存在公共前缀。

class Solution():

    def __init__(self):

        pass

    def longestCommonPrefix(self, strs):

        """

        :type strs: List[str]

        :rtype: str

        """

        list_len = len(strs)

        if list_len > 1:

            str_len = min(len(f) for f in strs)

            longest_substr = ""

            for j in range(0, str_len):

                c = strs[0][j]

                index = 0

                for i in range(1, list_len):

                    if c == strs[i][j]:

                        index += 1

                        print strs[i][j]

                if index == (list_len-1):

                    longest_substr += c

                else:

                    return longest_substr

            return longest_substr

        else:

            if list_len == 1:

                return strs[0]

            else:

                return ""

    def longestCommonPrefix2(self, strs):

        res = ""

        if len(strs) == 0:

            return ""

        # zip()函数用于将可迭代对象作为参数，将对象中对应的元素打包成一个个元组，然后返回由这些元组组成的列表

        for each in zip(*strs):

            # print each  # each 是由strs字符串列表中每一个对象的对应位置的元素组成的元祖。

            # 利用集合创建一个无序不重复元素集

            print(set(each))

            if len(set(each)) == 1:

                res += each[0]

            else:

                return res

        return res

if __name__ == "__main__":

    strs = ["dog", "racecar", "car"]

    strs = ["flower", "flow", "flight"]

    # strs = ["dog"]

    # strs = ["aca", "cba"]

    answer = Solution()

    print answer.longestCommonPrefix2(strs)