14. Longest Common Prefix {Easy}

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.

本题应有多种解题思路，包括分治法，二叉树等。

Dr_Sean's solution:

class Solution:
    def longestCommonPrefix(self, strs):
        """
        :type strs: List[str]
        :rtype: str
        """
        if strs == []: return ""
        elif len(strs) == 1: return strs[0]
        else:
            LCP, k = '', 0
            while k < len(strs[0]):
                j, status = 1, False
                while j < len(strs):
                    if strs[0][0:k+1] == strs[j][0:k+1]: 
                        status, j = True, j + 1
                    else:
                        // j = len(strs) 结束循环， k = len(strs[0]) 结束外层循环
                        j, k, status = len(strs), len(strs[0]), False
                if status:
                    LCP = strs[0][0:k+1]
                k += 1
            return LCP