Number of distinct subsequences
Easy Accuracy: 28.84% Submissions: 1693 Points: 2

Given a string consisting of lower case English alphabets, the task is to find the number of distinct subsequences of the string
Note: Answer can be very large, so, ouput will be answer modulo 109+7

Example 1:

Input: s = "gfg"
Output: 7
Explanation: The seven distinct
subsequences are "", "g", "f", "gf", "fg",
"gg" and "gfg" 

Example 2:

Input: s = "ggg"
Output: 4
Explanation: The four distinct
subsequences are "", "g", "gg", "ggg"

You do not need to read any input or print anything. The task is to complete the function distinctSubsequences(), which takes a string as input and returns an integer.

Expected Time Complexity: O(|str|)
Expected Auxiliary Space: O(|str|)

Constraints:
1 ≤ |s| ≤ 105
s contains lower case English alphabets

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