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DSUBSEQ - Distinct Subsequences |
Given a string, count the number of distinct subsequences of it (including empty subsequence). For the uninformed, a subsequence of a string is a new string which is formed from the original string by deleting some of the characters without disturbing the relative positions of the remaining characters.
For example, "AGH" is a subsequence of "ABCDEFGH" while "AHG" is not.
Input
First line of input contains an integer T which is equal to the number of test cases. You are required to process all test cases. Each of next T lines contains a string s.
Output
Output consists of T lines. Ith line in the output corresponds to the number of distinct subsequences of ith input string. Since, this number could be very large, you need to output ans%1000000007 where ans is the number of distinct subsequences.
Example
Input: 3 AAA ABCDEFG CODECRAFT Output: 4 128 496
Constraints and Limits
T ≤ 100, length(S) ≤ 100000
All input strings shall contain only uppercase letters.
Added by: | Ajay Somani |
Date: | 2008-02-05 |
Time limit: | 1s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: CPP |
Resource: | CodeCraft 08, Problem Setter: Jin Bin |
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2019-05-06 11:17:37
solvable in python play ez .not much optimization required just use dp and standard input output |
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2019-04-30 12:24:11
@deepak097 thanks for spoiling the problem :( |
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2019-03-28 06:37:58
Got AC :) complexity- O(n*26) |
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2019-01-05 19:47:50
Very very Good DP Question with interesting optimization. It took a lot of time to crack this. |
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2018-05-17 12:52:39
Nice problem!! |
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2017-12-20 11:32:09
dynamic programing easy |
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2017-10-28 23:37:16
Yes, it is important to add 'mod' wherever the answer can be negative. GeeksforGeeks tutorial might be helpful. |
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2017-09-25 09:27:12
take care of mod.Cost me 1WA |
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2017-06-29 09:01:15
One of the finest problem....loved to solve it :) |
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2017-06-16 14:12:19
take care about MOD !! cost me 1 WA !! |