https://leetcode.com/problems/plus-one-linked-list/

Given a non-negative integer represented as **non-empty** a singly linked list of digits, plus one to the integer.

You may assume the integer do not contain any leading zero, except the number 0 itself.

The digits are stored such that the most significant digit is at the head of the list.

**Example :**

Input:[1,2,3]Output:[1,2,4]