leetcode-problemset/leetcode/problem/compare-version-numbers.html

<p>Given two version numbers,&nbsp;<code>version1</code> and <code>version2</code>, compare them.</p>

<ul>
</ul>

<p>Version numbers consist of <strong>one or more revisions</strong> joined by a dot&nbsp;<code>&#39;.&#39;</code>. Each revision&nbsp;consists of <strong>digits</strong>&nbsp;and may contain leading <strong>zeros</strong>. Every revision contains <strong>at least one character</strong>. Revisions are <strong>0-indexed from left to right</strong>, with the leftmost revision being revision 0, the next revision being revision 1, and so on. For example&nbsp;<code>2.5.33</code>&nbsp;and&nbsp;<code>0.1</code>&nbsp;are valid version numbers.</p>

<p>To compare version numbers, compare their revisions in <strong>left-to-right order</strong>. Revisions are compared using their&nbsp;<strong>integer value ignoring any leading zeros</strong>. This means that revisions&nbsp;<code>1</code>&nbsp;and&nbsp;<code>001</code>&nbsp;are considered&nbsp;<strong>equal</strong>. If a version number does not specify a revision at an index, then&nbsp;<strong>treat the revision as&nbsp;<code>0</code></strong>. For example, version&nbsp;<code>1.0</code> is less than version&nbsp;<code>1.1</code>&nbsp;because their revision 0s are the same, but their revision 1s are&nbsp;<code>0</code>&nbsp;and&nbsp;<code>1</code>&nbsp;respectively, and&nbsp;<code>0 &lt; 1</code>.</p>

<p><em>Return the following:</em></p>

<ul>
	<li>If <code>version1 &lt; version2</code>, return <code>-1</code>.</li>
	<li>If <code>version1 &gt; version2</code>, return <code>1</code>.</li>
	<li>Otherwise, return <code>0</code>.</li>
</ul>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> version1 = &quot;1.01&quot;, version2 = &quot;1.001&quot;
<strong>Output:</strong> 0
<strong>Explanation:</strong> Ignoring leading zeroes, both &quot;01&quot; and &quot;001&quot; represent the same integer &quot;1&quot;.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> version1 = &quot;1.0&quot;, version2 = &quot;1.0.0&quot;
<strong>Output:</strong> 0
<strong>Explanation:</strong> version1 does not specify revision 2, which means it is treated as &quot;0&quot;.
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> version1 = &quot;0.1&quot;, version2 = &quot;1.1&quot;
<strong>Output:</strong> -1
<strong>Explanation:</strong> version1&#39;s revision 0 is &quot;0&quot;, while version2&#39;s revision 0 is &quot;1&quot;. 0 &lt; 1, so version1 &lt; version2.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= version1.length, version2.length &lt;= 500</code></li>
	<li><code>version1</code> and <code>version2</code>&nbsp;only contain digits and <code>&#39;.&#39;</code>.</li>
	<li><code>version1</code> and <code>version2</code>&nbsp;<strong>are valid version numbers</strong>.</li>
	<li>All the given revisions in&nbsp;<code>version1</code> and <code>version2</code>&nbsp;can be stored in&nbsp;a&nbsp;<strong>32-bit integer</strong>.</li>
</ul>