DISUBSTR - Distinct Substrings
Given a string, we need to find the total number of its distinct substrings.
T- number of test cases. T<=20;
Each test case consists of one string, whose length is <= 1000
For each test case output one number saying the number of distinct substrings.
Explanation for the testcase with string ABABA:
len=1 : A,B
len=2 : AB,BA
len=3 : ABA,BAB
len=4 : ABAB,BABA
len=5 : ABABA
Thus, total number of distinct substrings is 9.
vector of suffixes of string and sorting 0.01s
suffix tree :D
Try this case:
I was kind of intimidated by this problem, because I thought the standard implementations were pretty complicated and I didn't want to learn all the nitty gritty details. Understanding how the LCP array and suffix array work together was enough, then I just constructed them ad hoc. The runtime was good enough at 0.02s, and I still got a lot out of it. I'll wait for harder problems to do the better big O constructions.Last edit: 2016-10-22 08:31:29
Learnt a whole lot about string algos through this problem. Probably the toughest one on strings I ever solved. Dont assume the characters to be alphabetical, dont subtract 'A' in deciding the rank. I got many WA's because of that.
If you use suffix array, you can solve for O(n). So I was able to get 0.00s.
Awesome Problem!! Learnt a lot.
My solution using suffix arrays giving wrong answer : https://ideone.com/pd9BQB .Please help ! Same code worked well for NEW DISTINCT SUBSTRINGS :O
If you write an O(n) algorithm of suffix array(such as "DC3" or "SA-IS") , you just need to calculate the LCP of every two suffix which rank is nearby,then you just use sigma(1~lenth(string)) minus sigma(i=1 to lenth(string))height i; the answer will be calculated. The whole algorithm will be O(n).
kmp rocks :)