Package 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 java.lang.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
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    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 Details

    • Solution

      public Solution()

  • Method Details

    • countGoodStrings

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