### Aulene's blog

By Aulene, history, 9 months ago, ,

Problem K: We had some ideas to model this problem as a graph problem and have edges between people (modeled as nodes) if they had conflicts. This approach is probably incorrect and I don't really have ideas, so help would be appreciated.

Problem G: Given that the agents arrived in order a, b, c, the probability of success should be P(t_b — t_a < w_a) * P(t_c — t_b < w_b) = w_a * w_b / S^2. Then we considered all permutations, which should give a probability of success of (w_a * w_b + w_a * w_c + w_b * w_c) / (3 * S^3). But this gave WA on Test 6. Any insights?

Thank you!

• +1

By Aulene, history, 12 months ago, ,

Hi,

I was recently trying the aforementioned question. My idea was: I can find all primes up to 1e6, after that I can do the prime decomposition of each of the v[i] and find the overall prime decomposition of a, in the form p_1^x_1 * p_2^x_2 .. p_n^x_n.

But after this, I'm stuck with how to find the number of divisors of a number (from its prime decomposition) that have exactly b divisors.

Any help would be highly appreciated!