mirror of
https://gitee.com/coder-xiaomo/leetcode-problemset
synced 2025-01-10 18:48:13 +08:00
50 lines
1.7 KiB
HTML
50 lines
1.7 KiB
HTML
<p>You are given a string <code>num</code> representing a large integer. An integer is <strong>good</strong> if it meets the following conditions:</p>
|
|
|
|
<ul>
|
|
<li>It is a <strong>substring</strong> of <code>num</code> with length <code>3</code>.</li>
|
|
<li>It consists of only one unique digit.</li>
|
|
</ul>
|
|
|
|
<p>Return <em>the <strong>maximum good </strong>integer as a <strong>string</strong> or an empty string </em><code>""</code><em> if no such integer exists</em>.</p>
|
|
|
|
<p>Note:</p>
|
|
|
|
<ul>
|
|
<li>A <strong>substring</strong> is a contiguous sequence of characters within a string.</li>
|
|
<li>There may be <strong>leading zeroes</strong> in <code>num</code> or a good integer.</li>
|
|
</ul>
|
|
|
|
<p> </p>
|
|
<p><strong class="example">Example 1:</strong></p>
|
|
|
|
<pre>
|
|
<strong>Input:</strong> num = "6<strong><u>777</u></strong>133339"
|
|
<strong>Output:</strong> "777"
|
|
<strong>Explanation:</strong> There are two distinct good integers: "777" and "333".
|
|
"777" is the largest, so we return "777".
|
|
</pre>
|
|
|
|
<p><strong class="example">Example 2:</strong></p>
|
|
|
|
<pre>
|
|
<strong>Input:</strong> num = "23<strong><u>000</u></strong>19"
|
|
<strong>Output:</strong> "000"
|
|
<strong>Explanation:</strong> "000" is the only good integer.
|
|
</pre>
|
|
|
|
<p><strong class="example">Example 3:</strong></p>
|
|
|
|
<pre>
|
|
<strong>Input:</strong> num = "42352338"
|
|
<strong>Output:</strong> ""
|
|
<strong>Explanation:</strong> No substring of length 3 consists of only one unique digit. Therefore, there are no good integers.
|
|
</pre>
|
|
|
|
<p> </p>
|
|
<p><strong>Constraints:</strong></p>
|
|
|
|
<ul>
|
|
<li><code>3 <= num.length <= 1000</code></li>
|
|
<li><code>num</code> only consists of digits.</li>
|
|
</ul>
|