Package g1901_2000.s1987_number_of_unique_good_subsequences

Class Solution

  • All Implemented Interfaces:
    
public final class Solution

    1987 - Number of Unique Good Subsequences\.

    Hard

    You are given a binary string binary. A subsequence of binary is considered good if it is not empty and has no leading zeros (with the exception of "0").

    Find the number of unique good subsequences of binary.

    • For example, if binary = "001", then all the good subsequences are ["0", "0", "1"], so the unique good subsequences are "0" and "1". Note that subsequences "00", "01", and "001" are not good because they have leading zeros.

    Return the number of unique good subsequences of binary. Since the answer may be very large, return it modulo <code>10<sup>9</sup> + 7</code>.

    A subsequence is a sequence that can be derived from another sequence by deleting some or no elements without changing the order of the remaining elements.

    Example 1:

    Input: binary = "001"

    Output: 2

    Explanation: The good subsequences of binary are "0", "0", "1".

    The unique good subsequences are "0" and "1".

    Example 2:

    Input: binary = "11"

    Output: 2

    Explanation: The good subsequences of binary are "1", "1", "11".

    The unique good subsequences are "1" and "11".

    Example 3:

    Input: binary = "101"

    Output: 5

    Explanation: The good subsequences of binary are "1", "0", "1", "10", "11", "101".

    The unique good subsequences are "0", "1", "10", "11", and "101".

    Constraints:

    • <code>1 <= binary.length <= 10<sup>5</sup></code>

    • binary consists of only '0's and '1's.

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Constructor Summary

      Constructors 
      Constructor Description
      Solution()

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description

    • Method Summary

      Modifier and Type Method Description
      final Integer numberOfUniqueGoodSubsequences(String binary)

      • Methods inherited from class java.lang.Object

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