LeetCode14_最长公共前缀

1. 题目

编写一个函数来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 ""。

示例 1：
输入：strs = ["flower","flow","flight"]
输出："fl"

示例 2：
输入：strs = ["dog","racecar","car"]
输出：""
解释：输入不存在公共前缀。
 

提示：
1 <= strs.length <= 200
0 <= strs[i].length <= 200
strs[i]

2. 题解

from typing import List


class Solution:
    # 方法1
    def longestCommonPrefix(self, strs: List[str]) -> str:
        result = ""
        if len(strs) == 0:
            return result
        else:
            result = strs[0]
        for i in range(1, len(strs)):
            result = self.sub_str(result, strs[i])
        return result

    def sub_str(self, str1, str2):
        res = ""

        for i in range(min(len(str1), len(str2))):
            if str1[i] == str2[i]:
                res = str1[:i + 1]
            else:
                res = str1[:i]
                break
        return res

    # 方法2
    def longestCommonPrefix_2(self, strs: List[str]) -> str:
        res = ""
        for i in zip(*strs):
            if len(set(i)) == 1:
                res += i[0]
            else:
                break
        return res

    # 方法3
    def longestCommonPrefix_3(self, strs: List[str]) -> str:
        if len(strs) == 0:
            return ''
        min_str = min(strs)
        max_str = max(strs)

        for i in range(len(min_str)):
            if min_str[i] != max_str[i]:
                return min_str[:i]
        return min_str


if __name__ == "__main__":
    s = Solution()
    strs = ["flower", "flow", "flight"]
    a = s.longestCommonPrefix_2(strs)
    print(a)