leetcode 14 Longest Common Prefix

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Sat Jan  6 16:11:51 2018

@author: vicky
"""

class Solution:
def longestCommonPrefix(self, strs):
"""
:type strs: List[str]
:rtype: str
"""
#string是“”，char是‘’
if len(strs)==0:
return ""
else:
p=strs[0]
for i in range(len(strs)-1):
t=str()
for j in range(min(len(p),len(strs[i+1]))):
#注意strs[]表示string，strs[][]表示第几个字母
if p[j]==strs[i+1][j]:
t=t+strs[i+1][j]
else:
break
p=t
return p

strs=["aa","aa"]
strs=["aca","cba"]
strs=["abc","abdf","acdg","abcfgh"]
Solution().longestCommonPrefix(strs)

from functools import reduce
#reduce()用法：跟r里面的apply类似
#    reduce(lambda x,y:x*y,range(1,3),5) //lambda 函数，5是初始值， 1*2*5
#    reduce(lambda x,y:x*y,range(1,6)) //阶乘，1*2*3*4*5
#    reduce(lambda x,y:x*y,range(1,6),3) //初始值3，结果再*3
#    http://www.cnblogs.com/zhoujinyi/archive/2013/06/07/3121976.html 
class Solution:
def longestCommonPrefix(self, strs):
def lcp(s, t):
if len(s)>len(t):
s, t = t, s
for i in range(len(s)):
if s[i]!=t[i]:
return s[:i]
return s
return reduce(lcp,strs) if strs else ""