leetcode-problemset/leetcode-cn/problem (English)/移除K-平衡子字符串(English) [remove-k-balanced-substrings].html

<p>You are given a string <code>s</code> consisting of <code>&#39;(&#39;</code> and <code>&#39;)&#39;</code>, and an integer <code>k</code>.</p>

<p>A <strong>string</strong> is <strong>k-balanced</strong> if it is <strong>exactly</strong> <code>k</code> <strong>consecutive</strong> <code>&#39;(&#39;</code> followed by <code>k</code> <strong>consecutive</strong> <code>&#39;)&#39;</code>, i.e., <code>&#39;(&#39; * k + &#39;)&#39; * k</code>.</p>

<p>For example, if <code>k = 3</code>, k-balanced is <code>&quot;((()))&quot;</code>.</p>

<p>You must <strong>repeatedly</strong> remove all <strong>non-overlapping k-balanced <span data-keyword="substring-nonempty">substrings</span></strong> from <code>s</code>, and then join the remaining parts. Continue this process until no k-balanced <strong>substring</strong> exists.</p>

<p>Return the final string after all possible removals.</p>

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

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">s = &quot;(())&quot;, k = 1</span></p>

<p><strong>Output:</strong> <span class="example-io">&quot;&quot;</span></p>

<p><strong>Explanation:</strong></p>

<p>k-balanced substring is <code>&quot;()&quot;</code></p>

<table style="border: 1px solid black;">
	<thead>
		<tr>
			<th style="border: 1px solid black;">Step</th>
			<th style="border: 1px solid black;">Current <code>s</code></th>
			<th style="border: 1px solid black;"><code>k-balanced</code></th>
			<th style="border: 1px solid black;">Result <code>s</code></th>
		</tr>
	</thead>
	<tbody>
		<tr>
			<td style="border: 1px solid black;">1</td>
			<td style="border: 1px solid black;"><code>(())</code></td>
			<td style="border: 1px solid black;"><code>(<s><strong>()</strong></s>)</code></td>
			<td style="border: 1px solid black;"><code>()</code></td>
		</tr>
		<tr>
			<td style="border: 1px solid black;">2</td>
			<td style="border: 1px solid black;"><code>()</code></td>
			<td style="border: 1px solid black;"><s><strong><code>()</code></strong></s></td>
			<td style="border: 1px solid black;">Empty</td>
		</tr>
	</tbody>
</table>

<p>Thus, the final string is <code>&quot;&quot;</code>.</p>
</div>

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

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">s = &quot;(()(&quot;, k = 1</span></p>

<p><strong>Output:</strong> <span class="example-io">&quot;((&quot;</span></p>

<p><strong>Explanation:</strong></p>

<p>k-balanced substring is <code>&quot;()&quot;</code></p>

<table style="border: 1px solid black;">
	<thead>
		<tr>
			<th style="border: 1px solid black;">Step</th>
			<th style="border: 1px solid black;">Current <code>s</code></th>
			<th style="border: 1px solid black;"><code>k-balanced</code></th>
			<th style="border: 1px solid black;">Result <code>s</code></th>
		</tr>
	</thead>
	<tbody>
		<tr>
			<td style="border: 1px solid black;">1</td>
			<td style="border: 1px solid black;"><code>(()(</code></td>
			<td style="border: 1px solid black;"><code>(<s><strong>()</strong></s>(</code></td>
			<td style="border: 1px solid black;"><code>((</code></td>
		</tr>
		<tr>
			<td style="border: 1px solid black;">2</td>
			<td style="border: 1px solid black;"><code>((</code></td>
			<td style="border: 1px solid black;">-</td>
			<td style="border: 1px solid black;"><code>((</code></td>
		</tr>
	</tbody>
</table>

<p>Thus, the final string is <code>&quot;((&quot;</code>.</p>
</div>

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

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">s = &quot;((()))()()()&quot;, k = 3</span></p>

<p><strong>Output:</strong> <span class="example-io">&quot;()()()&quot;</span></p>

<p><strong>Explanation:</strong></p>

<p>k-balanced substring is <code>&quot;((()))&quot;</code></p>

<table style="border: 1px solid black;">
	<thead>
		<tr>
			<th style="border: 1px solid black;">Step</th>
			<th style="border: 1px solid black;">Current <code>s</code></th>
			<th style="border: 1px solid black;"><code>k-balanced</code></th>
			<th style="border: 1px solid black;">Result <code>s</code></th>
		</tr>
	</thead>
	<tbody>
		<tr>
			<td style="border: 1px solid black;">1</td>
			<td style="border: 1px solid black;"><code>((()))()()()</code></td>
			<td style="border: 1px solid black;"><code><s><strong>((()))</strong></s>()()()</code></td>
			<td style="border: 1px solid black;"><code>()()()</code></td>
		</tr>
		<tr>
			<td style="border: 1px solid black;">2</td>
			<td style="border: 1px solid black;"><code>()()()</code></td>
			<td style="border: 1px solid black;">-</td>
			<td style="border: 1px solid black;"><code>()()()</code></td>
		</tr>
	</tbody>
</table>

<p>Thus, the final string is <code>&quot;()()()&quot;</code>.</p>
</div>

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

<ul>
	<li><code>2 &lt;= s.length &lt;= 10<sup>5</sup></code></li>
	<li><code>s</code> consists only of <code>&#39;(&#39;</code> and <code>&#39;)&#39;</code>.</li>
	<li><code>1 &lt;= k &lt;= s.length / 2</code></li>
</ul>