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вернуться в форумTLE Послано KIRILL 27 сен 2006 00:41 my simple algo don't fit if compute on each step number of UFO wich belong to sector - its too long (O(n*n)) What's the correct algo for this task? Re: TLE You should use cumulative tables... Re: TLE Octtrees also didn't work! Is there quicker data structure? I've used 3d Fenwick's tree to get AC (-) Re: TLE Послано CHN_XT 12 окт 2006 13:52 Tree Array, like Mobile(IOI2001). Re: TLE Послано lijian 9 июл 2007 10:54 Should call'Binary Indexed Tree' Help!!! I use cumulative tables... But I get TLE 5 =( A[i][j][k][d]=Sum[{i*2^d,j*2^d,k*2^d}:{(i+1)*2^d-1,(j+1)*2^d-1,(k+1)*2^d-1}] I can add the UFO by log(n) time, but the calculation of the total number of UFOs in a sector are too long... =( For example, if N=128 and x1=1, y1=1, z1=1, x2=126, y2=126, z2=126 - my algo gives O(n^2) time... =( No subject My AC program is O((log N)^3) time Re: No subject Mine's too (base4 due to ML). 1.47 sec Fenwick tree - AC 0.5sec on Java. Re: Fenwick tree - AC 0.5sec on Java. Hm... My solution uses segment tree in plain array as underlying data structure and it runs in O(n log n) but I've got TLE 6. Probably it's because I've used java and created a lot of objects while processing. Will try to tune performance to fit in time bound. Re: Fenwick tree - AC 0.5sec on Java. Got the same problem with segment tree and TLE 6, even though I use C++(( |
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