Reverse Words in a String

Problem Statement

Given an input string s, reverse the order of the words.

A word is defined as a sequence of non-space characters. The words in s will be separated by at least one space.

Return a string of the words in reverse order concatenated by a single space.

Note that s may contain leading or trailing spaces or multiple spaces between two words. The returned string should only have a single space separating the words. Do not include any extra spaces.

Leetcode link

Example 1:

Input: s = "the sky is blue"
Output: "blue is sky the"

Example 2:

Input: s = "  hello world  "
Output: "world hello"
Explanation: Your reversed string should not contain leading or trailing spaces.

Example 3:

Input: s = "a good   example"
Output: "example good a"
Explanation: You need to reduce multiple spaces between two words to a single space in the reversed string.

Constraints:

• 1 <= s.length <= 10⁴
• s contains English letters (upper-case and lower-case), digits, and spaces ' '.
• There is at least one word in s.

Code

Python Code

class Solution:
    def reverseWords(self, s: str) -> str:
        return " ".join(s.split()[::-1])

C++ Code

class Solution
{
public:
    string reverseWords(string s)
    {
        stringstream ss(s);
        string rev, w;

        ss >> rev;
        while (ss >> w) rev = w + " " + rev;

        return rev.substr(0, rev.length());
    }
};