Nov 112014
 

E. Lagged Speed

Author: Alham Fikri Aji
Prepared By: Alham Fikri Aji, Suhendry Effendy
(link to problem E)

I don’t like this problem. I didn’t mean it’s not a good problem, but I hate it because this problem made me stress πŸ˜›

You can solve this problem in two ways: by observing the values, or by finding the pattern. I solved this problem using the former method. With the help of drawing tool (I used gnuplot), I observed that there are two line shapes made by the speed changes (S), i.e. (1) increasing head, and (2) bouncing and converging tail. From there, I “only” need to derived the formula for those two shapes. However, this “only” task took me 1 hour. Another approach is by finding the pattern. As I don’t like this approach, I didn’t use it. But some contestants said that this appraoch is much easier. I also noticed that most of the accepted submissions used this approach – one line formula.

There are 156 submissions have been made for this problem, in which 12 teams managed to get accepted. The first team who solve this problem is GantengGantengKoder (minute 164) from Institut Teknologi Bandung.


  27 Responses to “ACM-ICPC INC 2014”

  1. “One popular approach was by first sorting all the strings and pair each succesive string whenever possible”, kode saya spt itu, hanya saja pasangkan dr yg terpanjang http://ideone.com/PGjPAq

  2. komen untuk prob J

    β€œOne popular approach was by first sorting all the strings and pair each succesive string whenever possible”, kode saya spt itu, hanya saja pasangkan dr yg terpanjang http://ideone.com/PGjPAq

    • koreksi, prob G

    • Ngga, kode kamu nggak seperti itu. Approach kamu itu jadi sama dengan approach greedy yang bener (pasangin dari leaves) — string yang paling panjang saat itu pasti leaf.

      Yang dimaksud “pair each succesive string whenever possible” itu comparenya bener-bener cuma sama 1 string di sebelahnya aja (sorted); sedangkan kamu compare dengan yang panjangnya lebih pendek.

  3. a bit curious about problem H. Did you use the real Kawal Pemilu data for judge’s test case? πŸ˜€

  4. nice problem, nice editorial, pretty helpful, thx πŸ™‚

  5. saya penasaran dgn problem yg blm sempat saya kerjakan (dan AC), apakah mungkin akan diupload ke situs online judge ?

    saya dpt ide sederhana utk problem J dgn menelusuri apakah suatu nilai bisa jadi pivot (menjadi ‘L’), setelah itu cek apakah bs dr index tersebut menjadi good segment, jika tidak cetak impossible, kode saya : [[REMOVED]]

    thx koreksinya πŸ˜€

  6. How about ACM-ICPC 2014 Jakarta write up?? Will it be published?

  7. How can I get input data ?

    Thank you for sharing.

    • Ah… I didn’t notice this comment before >.< I'll not share the input data publicly. You can test your solution in some online-judges, e.g., tokilearning or joj. (I think) I have sent the test data to the admin on those sites.

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