g2401_2500.s2466_count_ways_to_build_good_strings

Class Solution

java.lang.Object

g2401_2500.s2466_count_ways_to_build_good_strings.Solution

public class Solution
extends Object

2466 - Count Ways To Build Good Strings.

Medium

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.

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

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
int	countGoodStrings(int low, int high, int zero, int one)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

countGoodStrings

public int countGoodStrings(int low,
                            int high,
                            int zero,
                            int one)