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: strs = ["flower","flow","flight"]
Output: "fl"
Example 2:
Input: strs = ["dog","racecar","car"]
Output: ""
Explanation: There is no common prefix among the input strings.
Solution:
class Solution(object):
def longestCommonPrefix(self, strs):
"""
:type strs: List[str]
:rtype: str
"""
if not strs: # 如果列表为空，则返回一个空字符串
return ""
prefix = strs[0]
for s in strs[1:]:
while not s.startswith(prefix):
prefix = prefix[:-1] # prefix[:-1]表示选取前缀prefix序列中除了最后一个字符以外的所有字符
if not prefix: # 如果最终没有找到任何前缀，则返回一个空字符串
return ""
return prefix