How to Solve Reverse Words in a String on LeetCode
The Reverse Words in a String problem is a common test of string manipulation skills.
Problem Statement
Given an input string s, reverse the order of the words. A word is defined as a sequence of non-space characters.
Example:
Input: s = "the sky is blue"
Output: "blue is sky the"
Why This Problem Matters for Interviews
- Assesses your ability to manipulate strings
- Checks for handling whitespace and edge cases
- Appears often in interviews due to its simplicity
Approach to Reverse Words in a String
Split, Reverse, and Join (Optimal)
Trim, split, reverse, and join the words.
Time Complexity: O(n)
Space Complexity: O(n)
def reverseWords(s):
return ' '.join(s.strip().split()[::-1])
Key Interview Talking Points
- Why splitting and reversing works efficiently
- How to handle multiple spaces and leading/trailing spaces
- In-place reversal follow-up
Big O Complexity Recap
| Approach | Time Complexity | Space Complexity |
|---|---|---|
| Split-Reverse-Join | O(n) | O(n) |
Pro Interview Tips
- Watch out for extra spaces
- Practice in-place reversal (advanced)
- Try coding without built-ins for practice