On 08/23/2018 04:42 AM, Bartholomew Furrow wrote:
We're looking at roughly 10^6 heap operations in 100 test cases, which is around 10^8 heap operations total. I'd expect that to run in 4 minutes or less in C++ no problem, but in Python I wouldn't be so confident. How long does it run for?

I don't know as the test cases aren't downloadable (and I've switched to another approach).

I was just wondering if it was an inaccuracy in the text or a bug. The relevant part is:

If the operations over |S| are efficient, this will run in quasilinear time. There are many data structures that support insertion, finding the maximum, and removal of the maximum in logarithmic time, including AVL trees, red-black trees, and heaps. Many languages have one such structure in their standard libraries (e.g., the |multiset| or |priority_queue| in C++, |TreeSet| in Java, and |heapq| module in Python). Since we take O(log *K*) time for each of K steps, the algorithm takes only O(*K* log *K*) time, which is fast enough to solve test set 2.



On Wed, Aug 22, 2018 at 5:36 PM Eugene Yarmash <[email protected] <mailto:[email protected]>> wrote:

    Hello. I've tried to solve the problem using Python's heapq
    module, but
    that gave me 'Time limit exceeded' for the 2nd test case. I've
    checked
    the analysis and it claims that this approach should work for the 2nd
    test case. Am I missing something here? My code:

    from heapq import heappop, heappush


    def main():
         T = int(input())  # the number of test cases

         for case in range(1, T+1):
             N, K = map(int, input().split())

             h = [-N]

             for _ in range(K):
                 chunk = -heappop(h)
                 if chunk & 1:
                     if chunk == 1:
                         min_s = max_s = 0
                     else:
                         min_s = max_s = chunk >> 1
                         heappush(h, -min_s)
                         heappush(h, -max_s)
                 else:
                     max_s = chunk >> 1
                     min_s = max_s - 1
                     heappush(h, -min_s)
                     heappush(h, -max_s)

             print('Case #{}: {} {}'.format(case, max_s, min_s))


    main()





-- Regards,
       Eugene

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Regards,
  Eugene

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