<p>You are given a string <code>s</code> consisting of lowercase English letters, and an integer <code>k</code>.</p>

<p>First, <strong>convert</strong> <code>s</code> into an integer by replacing each letter with its position in the alphabet (i.e., replace <code>&#39;a&#39;</code> with <code>1</code>, <code>&#39;b&#39;</code> with <code>2</code>, ..., <code>&#39;z&#39;</code> with <code>26</code>). Then, <strong>transform</strong> the integer by replacing it with the <strong>sum of its digits</strong>. Repeat the <strong>transform</strong> operation <code>k</code><strong> times</strong> in total.</p>

<p>For example, if <code>s = &quot;zbax&quot;</code> and <code>k = 2</code>, then the resulting integer would be <code>8</code> by the following operations:</p>

<ul>
	<li><strong>Convert</strong>: <code>&quot;zbax&quot; ➝ &quot;(26)(2)(1)(24)&quot; ➝ &quot;262124&quot; ➝ 262124</code></li>
	<li><strong>Transform #1</strong>: <code>262124 ➝ 2 + 6 + 2 + 1 + 2 + 4&nbsp;➝ 17</code></li>
	<li><strong>Transform #2</strong>: <code>17 ➝ 1 + 7 ➝ 8</code></li>
</ul>

<p>Return <em>the resulting integer after performing the operations described above</em>.</p>

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

<pre>
<strong>Input:</strong> s = &quot;iiii&quot;, k = 1
<strong>Output:</strong> 36
<strong>Explanation:</strong> The operations are as follows:
- Convert: &quot;iiii&quot; ➝ &quot;(9)(9)(9)(9)&quot; ➝ &quot;9999&quot; ➝ 9999
- Transform #1: 9999 ➝ 9 + 9 + 9 + 9 ➝ 36
Thus the resulting integer is 36.
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;leetcode&quot;, k = 2
<strong>Output:</strong> 6
<strong>Explanation:</strong> The operations are as follows:
- Convert: &quot;leetcode&quot; ➝ &quot;(12)(5)(5)(20)(3)(15)(4)(5)&quot; ➝ &quot;12552031545&quot; ➝ 12552031545
- Transform #1: 12552031545 ➝ 1 + 2 + 5 + 5 + 2 + 0 + 3 + 1 + 5 + 4 + 5 ➝ 33
- Transform #2: 33 ➝ 3 + 3 ➝ 6
Thus the resulting integer is 6.
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;zbax&quot;, k = 2
<strong>Output:</strong> 8
</pre>

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

<ul>
	<li><code>1 &lt;= s.length &lt;= 100</code></li>
	<li><code>1 &lt;= k &lt;= 10</code></li>
	<li><code>s</code> consists of lowercase English letters.</li>
</ul>

class Solution {
public:
    int getLucky(string s, int k) {
        stringstream ss_digits;
        for (const auto &c: s) ss_digits << c - 'a' + 1;
        
        string digits = ss_digits.str();
        int sum = 0;
        do {
            sum = 0;
            for (const auto &c: digits) sum += c - '0';
            digits = to_string(sum);
        } while (--k);

        return sum;
    }
};
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