Given an integer n, count the total number of digit 1 appearing in all non-negative integers less than or equal to n.
Example 1:
Input: n = 13
Output: 6
Example 2:
Input: n = 0
Output: 0
Constraints:
0 <= n <= 109
Given an integer n, count the total number of digit 1 appearing in all non-negative integers less than or equal to n.
Example 1:
Input: n = 13
Output: 6
Example 2:
Input: n = 0
Output: 0
Constraints:
0 <= n <= 109