LongestCommonPrefix

Problem

https://leetcode.com/problems/longest-common-prefix/

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.

Constraints:

1 <= strs.length <= 200
0 <= strs[i].length <= 200
strs[i] consists of only lowercase English letters if it is non-empty.

Solution

Iterate through each character in the shortest string and check if it is in all other strings in strs.

Pattern

Array, String, Trie

Code

from typing import List


def longestCommonPrefix(strs: List[str]) -> str:
    """Find longest common prefix of all strings in ``strs``.
    """
    shortest = min(strs, key=len)
    for i, char in enumerate(shortest):
        if any(other[i] != char for other in strs):
            return shortest[:i]
    return shortest

Test

>>> from LongestCommonPrefix import longestCommonPrefix
>>> longestCommonPrefix(['flower', 'flow', 'flight'])
'fl'
>>> longestCommonPrefix(['dog', 'racecar', 'car'])
''

LongestCommonPrefix.longestCommonPrefix(strs: List[str]) → str: Find longest common prefix of all strings in strs.