Python dynamic exercises Day17

Day17: Find the longest common prefix string

　　eg1: input : ["folwer", "flow", "flight"]  

　　 　　output : "fl"

　　eg2: input : ["dog", "racecar" , "car"]

　　 　　output : 空

# Python using the Max () and Min () function, may be compared to a string in Python. The ASCII row, for example: 'abb', 'aba', 'ABAC' maximum 'abb', minimum 'ABA' , you only need to compare the maximum to minimum common prefix string

# Red part of the explanation: the ASCII code,

a	b	b		1
a	b	a		3
a	b	a	c	2
equal	equal	big b	c large

#Python in, if not determined whether the variable None (none available behalf string, 0, empty list, empty dictionary, null Zu):

　　　　if strs is none

　　　　if not strs

　　　　if not (strs is none)

# Need to use the ASCII code:

		ASCII code
letter	a-z	97-122
	A-Z	65-90
digital	0-9	48-57

 

 1 def longestCommonPrefix(strs):
 2     if not strs:
 3         return " "
 4     s1 = min(strs)
 5     s2 = max(strs)
 6     for i,x in enumerate(s1):
 7         if x != s2[i]:
 8             return s2[:i]
 9     return s1
10 
11 if __name__ == "__main__":
12     strs =  ["flower", "flow", "flight"]
13     strs1 = ["dog", "racecar" , "car"]
14     print(longestCommonPrefix(strs))
15     print(longestCommonPrefix(strs1))

Output: