Stepping Numbers
Medium Accuracy: 53.2% Submissions: 1716 Points: 4

A number is called a stepping number if all adjacent digits have an absolute difference of 1, e.g. '321' is a Stepping Number while 421 is not. Given two integers n and m, find the count of all the stepping numbers in the range [n, m].

Examples:

Input1 : n = 0, m = 21
Output1 : 13
Stepping no's are 0 1 2 3 4 5 6 7 8
9 10 12 21

Input2 : n = 10, m = 15
Output2 : 2
Stepping no's are 10, 12

You don't need to read input or print anything. Your task is to complete the function steppingNumbers() which takes the integer N and integer M as input parameters and returns the number of stepping numbers in the range between n and m.

Expected Time Complexity: O(log(M))
Expected Auxiliary Space: O(SN) where SN is the number of stepping numbers in the range

Constraints:
0 ≤ N, M ≤ 106

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Stepping Numbers