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.
```

Example 4:

```Input: s = "  Bob    Loves  Alice   "
Output: "Alice Loves Bob"
```

Example 5:

```Input: s = "Alice does not even like bob"
Output: "bob like even not does Alice"
```

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`.

• Could you solve it in-place with `O(1)` extra space?

151. Reverse Words in a String
``````struct Solution;

impl Solution {
fn reverse_words(s: String) -> String {
s.split_whitespace().rev().collect::<Vec<&str>>().join(" ")
}
}

#[test]
fn test() {
let s: String = "the sky is blue".to_string();
let res: String = "blue is sky the".to_string();
assert_eq!(Solution::reverse_words(s), res);
}
``````