class Solution:
def longestCommonPrefix(self, strs: List[str]) -> str:
"""
Find the longest common prefix string among an array of strings.
Parameters:
strs (List[str]): The list of strings to analyze.
Returns:
str: The longest common prefix shared by the strings in the list.
If there is no common prefix, returns an empty string.
"""
# If the list is empty, return an empty string immediately.
if not strs:
return ""
# Start with the first string as the initial prefix candidate.
prefix = strs[0]
# Iterate over the remaining strings in the list.
for s in strs[1:]:
# Reduce the prefix until the current string starts with it.
while not s.startswith(prefix):
# Update the prefix by removing the last character.
prefix = prefix[:-1]
# If the prefix becomes empty, return an empty string.
if not prefix:
return ""
# Return the longest common prefix after processing all strings.
return prefix
Summary of Techniques and Approaches:
Iterative Prefix Reduction: The algorithm starts with the first string as the candidate prefix and iteratively reduces it until every other string in the list matches the prefix at the beginning. This method is efficient because it quickly narrows down the common prefix.
String Startswith Check: Using Python’s built-in startswith method to check if the current string begins with the candidate prefix makes the solution both elegant and concise.
Early Termination: The solution immediately terminates when the prefix becomes empty, ensuring that unnecessary comparisons are avoided. This approach is applicable to numerous problems where early exits can optimize performance.
General Applicability: These techniques are useful for a range of problems that involve common subsequence or substring detection. Whenever a common pattern must be extracted from an array or sequence, consider using a similar iterative filtering approach.