add-two-numbers-ii.md

<p>You are given two <b>non-empty</b> linked lists representing two non-negative integers. The most significant digit comes first and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.</p>

<p>You may assume the two numbers do not contain any leading zero, except the number 0 itself.</p>

<p><b>Follow up:</b><br />
What if you cannot modify the input lists? In other words, reversing the lists is not allowed.
</p>

<p>
<b>Example:</b>
<pre>
<b>Input:</b> (7 -> 2 -> 4 -> 3) + (5 -> 6 -> 4)
<b>Output:</b> 7 -> 8 -> 0 -> 7
</pre>
</p>