The challenge
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: ["flower","flow","flight"] Output: "fl"
Example 2:
Input: ["dog","racecar","car"] Output: "" Explanation: There is no common prefix among the input strings.
Note:
All given inputs are in lowercase letters a-z.
The solution in Python
def longestCommonPrefix(self, strs: List[str]) -> str:
# the return string
prefix = ''
# break words into groups using `zip` and `*`
# ["flower","flow","flight"] becomes:
# (('f', 'f', 'f'), ('l', 'l', 'l'), ('o', 'o', 'i'), ('w', 'w', 'g'))
for group in zip(*strs):
# if the characters don't match, then break
if not all(char==group[0] for char in group):
break
# otherwise, grow the prefix
prefix += group[0]
# return the prefix
return prefix