resulting-string-after-adjacent-removals

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Algorithms

You are given a string <code>s</code> consisting of lowercase English letters.

You must repeatedly perform the following operation while the string <code>s</code> has at least two consecutive characters:

<ul>
	<li>Remove the leftmost pair of adjacent characters in the string that are consecutive in the alphabet, in either order (e.g., <code>&#39;a&#39;</code> and <code>&#39;b&#39;</code>, or <code>&#39;b&#39;</code> and <code>&#39;a&#39;</code>).</li>
	<li>Shift the remaining characters to the left to fill the gap.</li>
</ul>

Return the resulting string after no more operations can be performed.

Note: Consider the alphabet as circular, thus <code>&#39;a&#39;</code> and <code>&#39;z&#39;</code> are consecutive.

&nbsp;
Example 1:

<div class="example-block">
Input: s = &quot;abc&quot;

Output: &quot;c&quot;

Explanation:

<ul>
	<li>Remove <code>&quot;ab&quot;</code> from the string, leaving <code>&quot;c&quot;</code> as the remaining string.</li>
	<li>No further operations are possible. Thus, the resulting string after all possible removals is <code>&quot;c&quot;</code>.</li>
</ul>
</div>

Example 2:

<div class="example-block">
Input: s = &quot;adcb&quot;

Output: &quot;&quot;

Explanation:

<ul>
	<li>Remove <code>&quot;dc&quot;</code> from the string, leaving <code>&quot;ab&quot;</code> as the remaining string.</li>
	<li>Remove <code>&quot;ab&quot;</code> from the string, leaving <code>&quot;&quot;</code> as the remaining string.</li>
	<li>No further operations are possible. Thus, the resulting string after all possible removals is <code>&quot;&quot;</code>.</li>
</ul>
</div>

Example 3:

<div class="example-block">
Input: s = &quot;zadb&quot;

Output: &quot;db&quot;

Explanation:

<ul>
	<li>Remove <code>&quot;za&quot;</code> from the string, leaving <code>&quot;db&quot;</code> as the remaining string.</li>
	<li>No further operations are possible. Thus, the resulting string after all possible removals is <code>&quot;db&quot;</code>.</li>
</ul>
</div>

&nbsp;
Constraints:

<ul>
	<li><code>1 &lt;= s.length &lt;= 105</code></li>
	<li><code>s</code> consists only of lowercase English letters.</li>
</ul>

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resultingString

高级工程师

Resulting String After Adjacent Removals

Stack

String

Simulation

给你一个由小写英文字母组成的字符串 <code>s</code>。

你&nbsp;必须&nbsp;在字符串 <code>s</code> 中至少存在两个&nbsp;连续&nbsp;字符时，反复执行以下操作：

<ul>
	<li>移除字符串中&nbsp;最左边&nbsp;的一对按照字母表&nbsp;连续&nbsp;的相邻字符（无论是按顺序还是逆序，例如 <code>'a'</code> 和 <code>'b'</code>，或 <code>'b'</code> 和 <code>'a'</code>）。</li>
	<li>将剩余字符向左移动以填补空隙。</li>
</ul>

当无法再执行任何操作时，返回最终的字符串。

注意：字母表是循环的，因此 <code>'a'</code> 和 <code>'z'</code> 也视为连续。

&nbsp;

示例 1：

<div class="example-block">
输入: s = "abc"

输出: "c"

解释:

<ul>
	<li>从字符串中移除 <code>"ab"</code>，剩下 <code>"c"</code>。</li>
	<li>无法进行进一步操作。因此，所有可能移除操作后的最终字符串为 <code>"c"</code>。</li>
</ul>
</div>

示例 2：

<div class="example-block">
输入: s = "adcb"

输出: ""

解释:

<ul>
	<li>从字符串中移除 <code>"dc"</code>，剩下 <code>"ab"</code>。</li>
	<li>从字符串中移除 <code>"ab"</code>，剩下 <code>""</code>。</li>
	<li>无法进行进一步操作。因此，所有可能移除操作后的最终字符串为 <code>""</code>。</li>
</ul>
</div>

示例 3：

<div class="example-block">
输入: s = "zadb"

输出: "db"

解释:

<ul>
	<li>从字符串中移除 <code>"za"</code>，剩下 <code>"db"</code>。</li>
	<li>无法进行进一步操作。因此，所有可能移除操作后的最终字符串为 <code>"db"</code>。</li>
</ul>
</div>

&nbsp;

提示:

<ul>
	<li><code>1 &lt;= s.length &lt;= 105</code></li>
	<li><code>s</code> 仅由小写英文字母组成。</li>
</ul>