Hoof, Paper, Scissors Triples
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You have probably heard of the game "Rock, Paper, Scissors". The cows like to
play a similar game they call "Hoof, Paper, Scissors".
The rules of "Hoof, Paper, Scissors" are simple. Two cows play against each
other. They both count to three and then each simultaneously makes a gesture
that represents either a hoof, a piece of paper, or a pair of scissors. Hoof
beats scissors (since a hoof can smash a pair of scissors), scissors beats paper
(since scissors can cut paper), and paper beats hoof (since the hoof can get a
papercut). For example, if the first cow makes a "hoof" gesture and the second a
"paper" gesture, then the second cow wins. Of course, it is also possible to
tie, if both cows make the same gesture.
Now there are \(N\) (\(3\le N\le 2\cdot 10^5\)) cows who want to play hoof paper
scissors, and they each independently have a strategy of drawing from some fixed
distribution. In particular, the \(i\)th cow's strategy is to play hoof, paper, or
scissors with probabilities
\(\left(\frac{h_i}{h_i+p_i+s_i}, \frac{p_i}{h_i+p_i+s_i}, \frac{s_i}{h_i+p_i+s_i} \right)\),
respectively.
How many distinct triples of cows (A,B,C) are there such that A beats B on
average, B beats C on average, and C beats A on average? We consider two triples
the same if one equals the other up to a cyclic shift.
Problem credits: Richard Qi
SCORING
- Inputs 2-3: \(N\le 10\)
- Inputs 4-9: \(N \le 7500\), the sum of \(N\) over all tests does not exceed \(10^4\)
- Inputs 10-21: No additional constraints.
Problem credits: Richard Qi
The first line contains \(T\) (\(1\le T\le 5\cdot 10^4\)), the number of independent
tests. Each test is specified in the following format:
The first line contains \(N\).
The next \(N\) lines each contain three non-negative integers \(h_i\), \(p_i\), \(s_i\)
(\(0\le h_i,p_i,s_i\le 10^9, h_i+p_i+s_i>0\)).
It is guaranteed that the sum of \(N\) over all tests does not exceed
Output the number of triples.
Note: The large size of integers involved in this problem may require the use
of 64-bit integer data types (e.g., a "long long" in C/C++).
2
4
1 0 0
1 0 0
0 1 0
0 0 1
10
20410069 21445597 257862632
114108992 287498302 113278897
607994331 143503714 631122722
337497016 270153603 320256324
633717786 631078144 493265815
202783212 612643590 560838949
713379081 42803063 58996167
293262767 470686180 220651551
656404313 408797935 345461691
959196297 827681918 5915193932
32For the first test, there are two triples: \((1, 3, 4)\) and \((2, 3, 4)\).
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Hoof, Paper, Scissors Triples
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Hoof, Paper, Scissors Triples