14.最长公共前缀

 1 class Solution(object):
 2     def longestCommonPrefix(self, strs):
 3         """
 4         :type strs: List[str]
 5         :rtype: str
 6         """
 7         if not strs:
 8             return ""
 9         length = len(strs)  # 取得list的长度
10         if length == 1:
11             print(strs[0])
12             return strs[0]
13 
14         strs.sort(key=len)  # 根据列表中的字符串长度排序
15         ans = ‘‘  # 返回值
16         for i in range(len(strs[0])):  # 以列表中长度最小的单词为基准进行遍历
17             for j in strs:  # 遍历列表中的每个字符串
18                 if j[i] != strs[0][i]:  # 如果列表中的字符串的对应下标是否相同
19                     return ans
20             else:
21                 ans += strs[0][i]  # 如果所有字符串下标都相同，更新最长公共前缀
22         return ans
23 
24     def longestCommonPrefix2(self, strs):
25         """
26         :type strs: List[str]
27         :rtype: str
28         """
29         if not strs:
30             return ""
31 
32         length = len(strs)  # 取得list的长度
33         # print("list长度：", length)
34         if length == 1:
35             print(strs[0])
36             return strs[0]
37 
38         ans = ""
39         ans = Solution().commonPrefix(strs[0], strs[1])
40         i = 1
41         if i == length:
42             print(ans)
43             return ans
44         else:
45             ans = Solution().commonPrefix(ans, strs[i])
46             # print(ans)
47             i += 1
48         print(ans)
49 
50     # 比较两个字符串的最长前缀
51     def commonPrefix(self, str0, str1):
52         if str0 == ‘‘: return str1
53         if str1 == ‘‘: return str0
54         if str0 == str1: return str0
55         len0=len(str0)
56         len1=len(str1)
57         h = min(len0, len1)
58         ans = ‘‘
59         i = 0
60         j = 0
61         # for k in range(length):
62         if str0[i] == str1[j]:
63             ans += str0[i]
64             i += 1
65             j += 1
66         else:
67             return ans