Append the character '0' zero times.

Append the character '1' one times.

This can be performed any number of times.

A good string is a string constructed by the above process having a length between low and high (inclusive).

Return the number of different good strings that can be constructed satisfying these properties. Since the answer can be large, return it modulo 10⁹ + 7.

Example 1:

Input: low = 3, high = 3, zero = 1, one = 1
Output: 8
Explanation: 
One possible valid good string is "011". 
It can be constructed as follows: "" -> "0" -> "01" -> "011". 
All binary strings from "000" to "111" are good strings in this example.

Example 2:

Input: low = 2, high = 3, zero = 1, one = 2
Output: 5
Explanation: The good strings are "00", "11", "000", "110", and "011".

Constraints:

1 <= low <= high <= 10⁵
1 <= zero, one <= low

22:T496,Given the integers `zero`, `one`, `low`, and `high`, we can construct a string by starting with an empty string, and then at each step perform either of the following: * Append the character `'0'` `zero` times. * Append the character `'1'` `one` times. This can be performed any number of times. A **good** string is a string constructed by the above process having a **length** between `low` and `high` ( **inclusive** ). Return _the number of **different** good strings that can be constructed satisfying these properties._ Since the answer can be large, return it **modulo** `109 + 7`.

Count Ways To Build Good Strings

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