leetcode-problemset/leetcode-cn/problem (English)/字符串转换后的长度 II(English) [total-characters-in-string-after-transformations-ii].html

<p>You are given a string <code>s</code> consisting of lowercase English letters, an integer <code>t</code> representing the number of <strong>transformations</strong> to perform, and an array <code>nums</code> of size 26. In one <strong>transformation</strong>, every character in <code>s</code> is replaced according to the following rules:</p>

<ul>
	<li>Replace <code>s[i]</code> with the <strong>next</strong> <code>nums[s[i] - &#39;a&#39;]</code> consecutive characters in the alphabet. For example, if <code>s[i] = &#39;a&#39;</code> and <code>nums[0] = 3</code>, the character <code>&#39;a&#39;</code> transforms into the next 3 consecutive characters ahead of it, which results in <code>&quot;bcd&quot;</code>.</li>
	<li>The transformation <strong>wraps</strong> around the alphabet if it exceeds <code>&#39;z&#39;</code>. For example, if <code>s[i] = &#39;y&#39;</code> and <code>nums[24] = 3</code>, the character <code>&#39;y&#39;</code> transforms into the next 3 consecutive characters ahead of it, which results in <code>&quot;zab&quot;</code>.</li>
</ul>

<p>Return the length of the resulting string after <strong>exactly</strong> <code>t</code> transformations.</p>

<p>Since the answer may be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</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;abcyy&quot;, t = 2, nums = [1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2]</span></p>

<p><strong>Output:</strong> <span class="example-io">7</span></p>

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

<ul>
	<li>
	<p><strong>First Transformation (t = 1):</strong></p>

	<ul>
		<li><code>&#39;a&#39;</code> becomes <code>&#39;b&#39;</code> as <code>nums[0] == 1</code></li>
		<li><code>&#39;b&#39;</code> becomes <code>&#39;c&#39;</code> as <code>nums[1] == 1</code></li>
		<li><code>&#39;c&#39;</code> becomes <code>&#39;d&#39;</code> as <code>nums[2] == 1</code></li>
		<li><code>&#39;y&#39;</code> becomes <code>&#39;z&#39;</code> as <code>nums[24] == 1</code></li>
		<li><code>&#39;y&#39;</code> becomes <code>&#39;z&#39;</code> as <code>nums[24] == 1</code></li>
		<li>String after the first transformation: <code>&quot;bcdzz&quot;</code></li>
	</ul>
	</li>
	<li>
	<p><strong>Second Transformation (t = 2):</strong></p>

	<ul>
		<li><code>&#39;b&#39;</code> becomes <code>&#39;c&#39;</code> as <code>nums[1] == 1</code></li>
		<li><code>&#39;c&#39;</code> becomes <code>&#39;d&#39;</code> as <code>nums[2] == 1</code></li>
		<li><code>&#39;d&#39;</code> becomes <code>&#39;e&#39;</code> as <code>nums[3] == 1</code></li>
		<li><code>&#39;z&#39;</code> becomes <code>&#39;ab&#39;</code> as <code>nums[25] == 2</code></li>
		<li><code>&#39;z&#39;</code> becomes <code>&#39;ab&#39;</code> as <code>nums[25] == 2</code></li>
		<li>String after the second transformation: <code>&quot;cdeabab&quot;</code></li>
	</ul>
	</li>
	<li>
	<p><strong>Final Length of the string:</strong> The string is <code>&quot;cdeabab&quot;</code>, which has 7 characters.</p>
	</li>
</ul>
</div>

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

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">s = &quot;azbk&quot;, t = 1, nums = [2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2]</span></p>

<p><strong>Output:</strong> <span class="example-io">8</span></p>

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

<ul>
	<li>
	<p><strong>First Transformation (t = 1):</strong></p>

	<ul>
		<li><code>&#39;a&#39;</code> becomes <code>&#39;bc&#39;</code> as <code>nums[0] == 2</code></li>
		<li><code>&#39;z&#39;</code> becomes <code>&#39;ab&#39;</code> as <code>nums[25] == 2</code></li>
		<li><code>&#39;b&#39;</code> becomes <code>&#39;cd&#39;</code> as <code>nums[1] == 2</code></li>
		<li><code>&#39;k&#39;</code> becomes <code>&#39;lm&#39;</code> as <code>nums[10] == 2</code></li>
		<li>String after the first transformation: <code>&quot;bcabcdlm&quot;</code></li>
	</ul>
	</li>
	<li>
	<p><strong>Final Length of the string:</strong> The string is <code>&quot;bcabcdlm&quot;</code>, which has 8 characters.</p>
	</li>
</ul>
</div>

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

<ul>
	<li><code>1 &lt;= s.length &lt;= 10<sup>5</sup></code></li>
	<li><code>s</code> consists only of lowercase English letters.</li>
	<li><code>1 &lt;= t &lt;= 10<sup>9</sup></code></li>
	<li><code><font face="monospace">nums.length == 26</font></code></li>
	<li><code><font face="monospace">1 &lt;= nums[i] &lt;= 25</font></code></li>
</ul>