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Number of distinct subsequences
Submissions: 6   Accuracy:

16.67%

  Difficulty: Easy   Marks: 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"

Your task:
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

** For More Input/Output Examples Use 'Expected Output' option **

Author: Hemang Sarkar


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