reverse-words-in-a-string

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Algorithms

Given an input string <code>s</code>, reverse the order of the words.

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

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

Note that <code>s</code> 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.

&nbsp;
Example 1:

<pre>
Input: s = &quot;the sky is blue&quot;
Output: &quot;blue is sky the&quot;
</pre>

Example 2:

<pre>
Input: s = &quot; hello world &quot;
Output: &quot;world hello&quot;
Explanation: Your reversed string should not contain leading or trailing spaces.
</pre>

Example 3:

<pre>
Input: s = &quot;a good example&quot;
Output: &quot;example good a&quot;
Explanation: You need to reduce multiple spaces between two words to a single space in the reversed string.
</pre>

&nbsp;
Constraints:

<ul>
	<li><code>1 &lt;= s.length &lt;= 104</code></li>
	<li><code>s</code> contains English letters (upper-case and lower-case), digits, and spaces <code>&#39; &#39;</code>.</li>
	<li>There is at least one word in <code>s</code>.</li>
</ul>

&nbsp;
Follow-up:&nbsp;If the string data type is mutable in your language, can&nbsp;you solve it&nbsp;in-place&nbsp;with&nbsp;<code data-stringify-type="code">O(1)</code>&nbsp;extra space?