ACM ICPC World Finals 2016. Phuket, Thailand.

Harvard University team: Johnny Ho (random.johnnyh), Scott Wu (scott_wu), Calvin Deng (dnkywin), Jelani Nelson (coach) (Robert L. Walton, Coach). Team got 3rd place (gold medal) and became North America region Champions.

Main contest.

What is it? Scott Wu communicates with an outside adviser? Team has more than three participants?

Intel Code Challenge Final Round will take place on Saturday, 8 October 15:05 MSK.

All users of the Codeforces can participate in it as in an usual round. The round will be rated and both divisions can participate. Pay attention to the time of the beginning of the round.

There will be 7 problems with statements in english and russian languages and 3 hours to solve them. Scoring distribution will be announced closer to the start of the round.

The problems were prepared by me — Vladislav Epifanov (vepifanov). I want to say thanks to Alexey Shmelev (ashmelev), Alexander Fetisov (AlexFetisov) and Vladislav Isenbaev (winger) for testing the problems, coordinator of the Codeforces Gleb Evstropov (GlebsHP) for his help with the contest preparation, and Mike Mirzayanov (MikeMirzayanov) for the Codeforces and Polygon systems.

UPD. Scoring distribution: 500-1000-1500-1500-2500-2500-2500. Since the round will be 3 hours long, the number of points for each task will decrease slower than in usual round.

UPD. 2 Due to some issues on one of sites for official participation in Intel Code Challenge we shifted the beginning of the round for 10 minutes. Sorry for the inconvenience.

UPD. 3

Final rating changes will be available after removing unfair participants.

Editorial will be published on Sunday, 9 October.

Editorial

UPD. 6

Photos from the onsite event.

Intel Code Challenge Elimination Round will take place on Saturday, 1 October 17:05 MSK. Only russian citizens from 18 to 27 years old can officially participate in this competition.

However, for all other users of the Codeforces it will be an usual round. The round will be rated and both divisions can participate.

There will be 6 problems and 2 hours to solve them. Scoring distribution will be announced closer to the start of the round.

The problems were prepared by me — Vladislav Epifanov (vepifanov). I want to say thanks to Alexey Shmelev (ashmelev), Alexander Fetisov (AlexFetisov) and Vladislav Isenbaev (winger) for testing the problems, coordinator of the Codeforces Gleb Evstropov (GlebsHP) for his help with the contest preparation, and Mike Mirzayanov (MikeMirzayanov) for the Codeforces and Polygon systems.

UPD. Scoring: 500-500-1000-1500-2000-2500.

UPD 2.

I must apologies for the problem C. We decided to simplify it in the last moment, and it turned out, that the simplified version of it already appeared on another online judge.

Anyway, I hope that the second round will be better than the first one.

Editorial for this round will be published on Sunday, 2 October.

UPD 3. Editorial

A. Towers
The total number of towers is equal to number of different numbers in this set. To get the maximum height of the tower, it was possible to calculate for each length the number of bars with this length, and from these numbers is to choose the maximum.

B. Computer Game
Constraints in the problem allows us to solve it this way: we keep the current number of health from the boss, and current summary damage from used scrolls per second. At the next step, we choose which scrolls we can use in the current second. Of all these, we find the scroll, which causes the most damage, and apply it. If at some point we could not use any of the scrolls, and the current damage in one second does not exceed regeneration, we deduce that there are no answers. Otherwise, continue to iterate the algorithm until the number hit points will be nonnegative.

C. Old Berland Language
One of the easiest to understand solutions of this problem is as follows: sort the words in ascending order of length, while remembering their positions in the source list. We will consistently build our set, starting with the short strings: strings of length one can only be strings "0" and "1". If the number of words of length one in a set are more than two, hence there are no answers. Add the desired number of strings of length one to answer, and remove it from the current list. Then look at the string of length two: each of the remaining strings of length one can be extended in two ways (having added to each of these symbols 0 and 1). Add the desired number of strings of length two in our answer, and then increase the length of the remaining strings by one. Continue this process, until we get all words from the input set. You can see that if at some moment the number of allowable words exceeded the number of remaining, the extra words can be ignored and solution takes O (N * the maximum length of input set) time.

D. Lesson Timetable

E. Trial for Chief

• The first step of color all the cells at a distance less than or equal to D in black color
  

• At the second step color all the cells at a distance less than or equal to D - 1 in white

• Etc.

• Russian
• English