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Discussion of Problem 1672. Droid fliesShen Yang I got Accepted using this approach [2] // Problem 1672. Droid flies 2 Mar 2017 11:41 divide three euler angle into 50 pieces each of them is 2*pi/50;enum each euler angles and compute minmimum max different of distance to three faces. for(alpha=0;alpha<=2*pi;alpha+=dtheta) { if(min_dist>compute(alpha)) { min_dist=compute(alpha); ch=alpha; } } low=ch-dtheta; high=ch+dtheta; then ternary search [low,high].. Do you understand? Shen Yang Re: I got Accepted using this approach [1] // Problem 1672. Droid flies 2 Mar 2017 12:13 hahaha ,15 ms... Orient Re: I got Accepted using this approach // Problem 1672. Droid flies 28 Jan 2018 18:16 Can it be solved using QR-decomposition? svr very easy [4] // Problem 1672. Droid flies 30 Jan 2009 11:25 This is most easy problem in last list on euler angles and optimization. But I tried 30 submissions on test 2 because taken columns of optimal rotation matrix but should take rows acording of nature of dual basis. Al.Cash Re: very easy [3] // Problem 1672. Droid flies 30 Jan 2009 17:26 I really appreciate that you help people solving hard problems ))) Now a few questions about your post. Is your solution complexity O(n^4) ? And do you mean one should output the tranposed rotation matrix (which is equal to the inverse matrix, because the rotation matrix is orthogonal) ? svr Re: very easy // Problem 1672. Droid flies 30 Jan 2009 19:13 My post has emotional nature only . I saw that only 1 solved 1672 and thought that problem really hard but it to appear of school level. But what to use: rows or columns is rather non evidence and your are all right about ortogonality. Without ortogonality we must inverse matrix of transformation but for ortogonal case just transpose is applicable. svr Re: very easy [1] // Problem 1672. Droid flies 30 Jan 2009 19:19 My post has emotional nature only . I saw that only 1 solved 1672 and thought that problem really hard but it to appear of school level. But what to use: rows or columns is rather non evidence and your are all right about ortogonality. Without ortogonality we must inverse matrix of transformation but for ortogonal case just transpose is applicable. P.S. My posts have also idea that all problems is excersises only and don't have the value to battle during years with. Al.Cash Re: very easy // Problem 1672. Droid flies 31 Jan 2009 00:43 I can't say that I spend too much time on some particular problems. But it's interesting for me to solve all problems from this contest. And it looks quite realistic thanks to your hints))
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