Plus One

A non-negative integer is stored as an array of its decimal digits, most significant first, with no leading zeros (except the number 0 itself). Add one to the number and return the resulting digit array. **Example 1:** ``` Input: digits = [1, 2, 3] Output: [1, 2, 4] ``` **Example 2:** ``` Input: digits = [4, 3, 2, 1] Output: [4, 3, 2, 2] ``` **Example 3:** ``` Input: digits = [9] Output: [1, 0] ```