题目

分析

可以使用归并的思想来做，每两个串left 和right合并出最长公共前缀res，然后res之间再合并。

python代码

class Solution(object):
    def longestCommonPrefix(self, strs):
        """
        :type strs: List[str]
        :rtype: str
        """
        if  not strs: return ""
        return self.mergeSort(strs,0,len(strs)-1)

    def mergeSort(self,strs,begin,end):
        if begin==end:
            return strs[begin]
        
        mid = (begin+end)>>1
        left = self.mergeSort(strs,begin,mid)
        right = self.mergeSort(strs,mid+1,end)
        return self.merge(left,right)

    def merge(self,left,right):
        if len(right)<len(left):
            left,right = right,left
        res = ""
        for i in range(len(left)):
            if left[i]==right[i]:
                res+=left[i]
            else:
                break
        return res