Can I optimize this?

Revision en4, by bradyawn, 2017-08-30 23:28:01

UPD: Thanks for all the help guys! I threw away my recursive solution and solved it with loops. (DP?) :>

Hello all,

While going through the USACO training pages problem "Number Triangles", I used a recursive function to calculate the answer. You can see the problem statement here: http://train.usaco.org/usacoprob2?a=nOEpHRAhtUw&S=numtri

I used recursion to try and solve it, but ran into a timeout on test case 6:

> Run 6: Execution error: Your program (`numtri') used more than the allotted runtime of 1 seconds (it ended or was stopped at 1.715 seconds) when presented with test case 6. It used 4312 KB of memory.

I realized that with the test data at hand, it made sense that my program would timeout.

Data:

199 
    1 
    0 1 
    0 1 0 
    0 1 0 1 
    0 1 0 1 0 
    0 1 0 1 0 1 
    0 1 0 1 0 1 0 
    0 1 0 1 0 1 0 1 
    0 1 0 1 0 1 0 1 0 
    0 1 0 1 0 1 0 1 0 1 
    0 1 0 1 0 1 0 1 0 1 0 
    ... [and more] ...

My question is, is it possible for me to optimize my recursive solution, or should I try to use a loop instead of recursion? All hints and advice would be appreciated. (No full solutions please.)

My code below (C++11):

History

 
 
 
 
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  Rev. Lang. By When Δ Comment
en4 English bradyawn 2017-08-30 23:28:01 113
en3 English bradyawn 2017-08-30 04:47:22 0 (published)
en2 English bradyawn 2017-08-30 04:45:38 1188
en1 English bradyawn 2017-08-30 04:37:40 2375 Initial revision (saved to drafts)