# 151 Reverse Words in a String

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.

Example 1:

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

Example 2:

``````Input: s = "  hello world  "
Output: "world hello"
``````

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`.

Follow-up: If the string data type is mutable in your language, can you solve it in-place with `O(1)` extra space?

 ``````1 2 3 `````` ``````class Solution: def reverseWords(self, s: str) -> str: return ' '.join(reversed(s.split()))``````
 ``````1 2 3 4 5 6 7 8 `````` ``````func reverseWords(s string) string { words := strings.Fields(s) n := len(words) for i:=0; i < n/2; i++ { words[i], words[n-i-1] = words[n-i-1], words[i] } return strings.Join(words, " ") }``````