• # For Solution

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 `109 + 7`.

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: Number of Unique Good Subsequences solution leetcode

```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: Number of Unique Good Subsequences solution leetcode

```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: Number of Unique Good Subsequences solution leetcode

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