0151.Reverse Words in a String

Link: 151. Reverse Words in a String-Medium
Track: Amazon Tag

Question

Restate the problem

• Given a string
  • The word order is revered
  • Words are separated by exactly one space
  • The result has np leading or trailing spaces

Edge Case

• single word: "word" → "word"
• Only spaces: " " → ""

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Method 1 - Pythonic Split + Join
Method 2 - O(1)

Method 1 - Pythonic Split + Join

Approach

• words = s.split() → list of words without empty tokens
• Reverse words
• Return " ".join(reversed_words)

Complexity

• Time Complexity: O(n)
• Space Complexity: O(n)

Code

class Solution:
    def reverseWords(self, s: str) -> str:
        words = s.split()
        
        words.reverse()
 
        res = " ".join(words)
        return res

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History

• Feb-15-2026 Peeked
  • str.split