2719 - Count of Integers\.

Hard

You are given two numeric strings num1 and num2 and two integers max_sum and min_sum. We denote an integer x to be good if:

• num1 <= x <= num2

• min_sum <= digit_sum(x) <= max_sum.

Return the number of good integers. Since the answer may be large, return it modulo <code>10⁹ + 7</code>.

Note that digit_sum(x) denotes the sum of the digits of x.

Example 1:

Input: num1 = "1", num2 = "12", min_sum = 1, max\_sum = 8

Output: 11

Explanation: There are 11 integers whose sum of digits lies between 1 and 8 are 1,2,3,4,5,6,7,8,10,11, and 12. Thus, we return 11.

Example 2:

Input: num1 = "1", num2 = "5", min_sum = 1, max\_sum = 5

Output: 5

Explanation: The 5 integers whose sum of digits lies between 1 and 5 are 1,2,3,4, and 5. Thus, we return 5.

Constraints:

• <code>1 <= num1 <= num2 <= 10²²</code>

• 1 <= min_sum <= max_sum <= 400