Package g1901_2000.s1987_number_of_unique_good_subsequences

Class Solution

java.lang.Object
g1901_2000.s1987_number_of_unique_good_subsequences.Solution
public class Solution extends java.lang.Object
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 109 + 7.

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:

  • 1 <= binary.length <= 105
  • binary consists of only '0's and '1's.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    numberOfUniqueGoodSubsequences(java.lang.String binary)
     

    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

    • numberOfUniqueGoodSubsequences

      public int numberOfUniqueGoodSubsequences(java.lang.String binary)