## Number of Unique Good Subsequences solution leetcode

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. Number of Unique Good Subsequences solution leetcode

Return *the number of unique good subsequences of *

`binary`

. Since the answer may be very large, return it **modulo**

`10`^{9} + 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:2Explanation:The good subsequences of binary are ["0", "0", "1"]. The unique good subsequences are "0" and "1".

**Example 2: Number of Unique Good Subsequences solution leetcode **

Input:binary = "11"Output:2Explanation:The good subsequences of binary are ["1", "1", "11"]. The unique good subsequences are "1" and "11".

**Example 3: Number of Unique Good Subsequences solution leetcode **

Input:binary = "101"Output:5Explanation:The good subsequences of binary are ["1", "0", "1", "10", "11", "101"]. The unique good subsequences are "0", "1", "10", "11", and "101".

**Constraints: Number of Unique Good Subsequences solution leetcode **

`1 <= binary.length <= 10`

^{5}`binary`

consists of only`'0'`

s and`'1'`

s.