A Stepping Number is an integer such that all of its adjacent digits have an absolute difference of exactly 1. For example, 321 is a Stepping Number while 421 is not.
Given two integers low and high, find and return a sorted list of all the Stepping Numbers in the range [low, high] inclusive.
Example 1:
Input: low = 0, high = 21 Output: [0,1,2,3,4,5,6,7,8,9,10,12,21]
Constraints:
0 <= low <= high <= 2 * 10^9