leetcode-problemset/leetcode/problem/add-to-array-form-of-integer.html

<p>The <strong>array-form</strong> of an integer <code>num</code> is an array representing its digits in left to right order.</p>

<ul>
	<li>For example, for <code>num = 1321</code>, the array form is <code>[1,3,2,1]</code>.</li>
</ul>

<p>Given <code>num</code>, the <strong>array-form</strong> of an integer, and an integer <code>k</code>, return <em>the <strong>array-form</strong> of the integer</em> <code>num + k</code>.</p>

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

<pre>
<strong>Input:</strong> num = [1,2,0,0], k = 34
<strong>Output:</strong> [1,2,3,4]
<strong>Explanation:</strong> 1200 + 34 = 1234
</pre>

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

<pre>
<strong>Input:</strong> num = [2,7,4], k = 181
<strong>Output:</strong> [4,5,5]
<strong>Explanation:</strong> 274 + 181 = 455
</pre>

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

<pre>
<strong>Input:</strong> num = [2,1,5], k = 806
<strong>Output:</strong> [1,0,2,1]
<strong>Explanation:</strong> 215 + 806 = 1021
</pre>

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

<ul>
	<li><code>1 &lt;= num.length &lt;= 10<sup>4</sup></code></li>
	<li><code>0 &lt;= num[i] &lt;= 9</code></li>
	<li><code>num</code> does not contain any leading zeros except for the zero itself.</li>
	<li><code>1 &lt;= k &lt;= 10<sup>4</sup></code></li>
</ul>