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" +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 <= 104s contains English letters (upper-case and lower-case), digits, and spaces ' '.s.+
Follow-up: If the string data type is mutable in your language, can you solve it in-place with O(1) extra space?