Non decreasing numbers with n digits
Detailed guide and Python implementation for the 'Non decreasing numbers with n digits' problem.
Problem Statement
Write a function count_non_decreasing(n) that returns the count of non-decreasing numbers with n digits. A number is non-decreasing if every digit is greater than or equal to the digit to its left. Leading zeros are allowed (e.g. 012 is non-decreasing).
- •1 <= n <= 20
Examples
count_non_decreasing(1)
10
All single digit numbers (0 to 9) are non-decreasing.
count_non_decreasing(2)
55
There are 55 non-decreasing numbers of 2 digits (like 00, 01, ..., 11, 12, ..., 99).
Need a Hint?
Edge Cases to Watch
- Empty input structures
- Single element inputs
- Large numerical bounds
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