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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 |
hide comments
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2017-05-31 16:30:49
Just add mod wherever you think the answer could be negative. Ex: ( (2*x - y) +m)%m Few testcases:- ABCABCABC=326 AABBAABBAA=139 MANANM=47 MISSISSIPPI=478 |
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2017-05-17 18:20:38
input contains lowercase characters also. cost me 3 WA |
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2017-04-03 21:33:39
Very nice Problem..... Just 8 lines of code... Accepted in 1 Go...!! |
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2017-03-24 15:50:27
GOOD problem! |
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2017-03-09 14:51:24
good dp. string to maths |
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2017-02-21 19:27:27
@Avik Sarkar how can the value be negative..please explain |
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2017-01-14 15:17:38
Always check output before submitting. Cost me 1 wa. :( Great question though!! Just observe the pattern :) |
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2017-01-07 19:53:04
FINALLY AC :) 4 WAs due to MOD :/ |
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2016-12-30 12:31:23
@VINAYAK if ur answer is negative.....just add MOD to ur answer |
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2016-12-29 14:05:45
Why will modulo here give negative answer? Last edit: 2016-12-29 14:31:38 |