Ripatti's blog

By Ripatti4 weeks ago, translation, In English

A div2. Required row is row that have only one star inside. Requred column is comumn that also have only one star inside. So, you can iterate over all rows/columns, calculate number of stars inside them and find the answer.

Authors are MikeMirzayanov, Gerald

Read more »

 
 
 
 
  • Vote: I like it  
  • +43
  • Vote: I do not like it  

By Ripatti4 weeks ago, translation, In English

Hello everyone!

Today is the second round of the Open Moscow Programming Championship By CROC will be. Start is planned at 19:00.

Competition will happen by usual rules of Codeforces, with hacks and score falling in process of time. All contestants who passed score no less than contectant of the 300-th place in the Round 1, can participate in the Round 2. Every other contestants can patricipate the Round 2 out of competition. Specially for contestants of the second division we prepared more easy unofficial problemset. The official problemset and the unnoficial one have some common tasks.

Round will be rated for all participants.

Some number of problems are waiting you. They are roughly ordered by the increasing complexity. Score distribution is standard for both divisions (500-1000-1500-2000-2500). Don’t forget that during contest your solutions will be tested on a small set of pretests. Testing on full testset will be after end of the round. Pretests can don’t cover all cases of input data, so you should test your solutions very carefully.

It is strictly forbidden to publish statements/solutions of the problems before round will be end. Also you shouldn’t to talk about problems, discuss some things about possible solutions of them. Let’s be honest! You can discuss problems after the end of round.

Top 50 contestant will be allowed to the Final Round. Also all contestant with score not less than score of the 50-th contestant will be passed.

The round was prepared by Ripatti, havaliza, Gerald, RAD, MikeMirzayanov, Delinur.

Good luck for all!

UPD. We remind that the final of the Open Championship of Moscow and Moscow Region Programming (CROC) take place on April 27 in the office of the CROC. Note that CROC does not pay for the road and residence of the finalists. All participants must arrive at the final in the office of the CROC (Moscow) in the morning on April 27.

After the competition all participants will be provided to fill the form on the ability to participate in the finals of the competition. The first 50 participants on the results of the competition, which will confirm their participation in the finals, will be invited to final competition. You can confirm participation in the finals during the day after the end of Round 2.

It is recommended to fill the form, regardless of your results in Round 2, as large number of participants can reject the participation in the final.

Read more »

 
 
 
 
  • Vote: I like it  
  • +115
  • Vote: I do not like it  

By Ripatti6 weeks ago, translation, In English

A. Naive solution in O(n) (some simulation all of n rounds) gets TL. Let’s speed up this solution. Let’s consider rounds on segments [1..mk], [mk+1..2mk], [2mk+1..3mk] and so on. You can see that results of games on these segments will repeat. So you can simulate over exactly one segment and then take into consideration them [n/(mk)] times ([x] is rounding down). Remainder of n%(mk) last rounds you can simulate separately. So you have O(mk) solution that easily fits into time limits.

Authors are Ripatti and Gerald

Read more »

 
 
 
 
  • Vote: I like it  
  • +103
  • Vote: I do not like it  

By Ripatti6 months ago, translation, In English

div2 A. In this problem you should find length of polyline, multiply it by k / 50 and output that you will recieve. Length of polyline is sum of lengths of its segments. You can calculate length of every segment using Pythagorean theorem: .

Read more »

 
 
 
 
  • Vote: I like it  
  • +40
  • Vote: I do not like it  

By Ripatti6 months ago, translation, In English

Hello everyone!

I am glad to welcome you on today round of Codeforces. I hope that recent color revolution and a more later time for start of round will make some variety into process of solving problems:)

An author of today problems is me. RAD helped me to prepare this round, Delinur translated statements into English.

Good luck.

UPD.

The round ended, ratings was updated.

Winners of div1:

1. Egor

2. tourist

3. unicef

4. sevenkplus

5. ivan.popelyshev


Winners of div2:

1.

2. cjtoribio

3. miraliv

4. adrianoo

5. majia5

Yippee!

Editorial.

Read more »

 
 
 
 
  • Vote: I like it  
  • +200
  • Vote: I do not like it  

By Ripatti8 months ago, In Russian


Сайт Ала Циммерманна вот уже долгое время лежит. Постоянные участники соревнований этого сайта долго ждали когда он вернется к рабочему состоянию и так и не дождались. Поэтому они создали свой собственный сайт и запустили свой контест в стиле azspcs с блэкджеком и студентками. Победитель получит ааавтомобиииль! футболку с логотипом ISS. Подробности по ссылке.

Read more »

 
 
 
 
  • Vote: I like it  
  • +31
  • Vote: I do not like it  

By Ripatti9 months ago, translation, In English

A. (link) Solution of this problem is written in the fourth paragraph of the statements. You should carefully read and implement it. Only one difficult part is how to to determine which card has higher rank. You can for every card iterate over array [ '6', '7', '8', '9', 'T', 'J', 'Q', 'K', 'A' ] and determine numbers of ranks in this array. Finally, just compare them.

Read more »

 
 
 
 

By Ripatti9 months ago, translation, In English

Good evening.

Today's round is mine, as the previous one. This round will be for participants of the second division. Participants of the first division can take part in the round out of competition.

RADConnectorit4.kp and MikeMirzayanov helped me to prepare this round. Delinur translated statements into English.

Contest will be in the good old tradition of Codeforces. No any innovations, pretty short and clear statements.

Points for problems are standard: 500-1000-1500-2000-2500.

Good luck everyone!


UPD. Round was ended, ratings was updated.

Winners:

1. tsundere

2. jte

3. abacadaea

4. ltaravilse

5. Billy_Herrington

Editorial.

Read more »

 
 
 
 

By Ripatti9 months ago, translation, In English

A. (link) In this problem you should do just that is written in the statement. At the first you should read all skills and multiply all levels of them by koefficient k. Next you should drop all skills which have level less than 100. After that you should add all new skills from the second list but only those thah are not present in the second list. At the end you should sort all skills by thier names and output them.

Read more »

 
 
 
 

By Ripatti9 months ago, translation, In English

Hello everyone!

I am the author of problems of today round. RADConnectorit4.kp helped me to prepere this contest. Delinur thanslated statements into english.

It will be a thematic contest. And the theme is Disgaea.

Is it possible to survive artef damage that is written by nine-digit number?
Of course, if amount of your health points is ten-digit number.
fans about Disgaea

Disgaea: Hour of Darkness is tactical RPG video game for consoles Playstation 2, PSP и Nintendo DS. So, get acquainted:

Etna, Laharl and Flonne - main characters of the game

The problems involves some aspects of the game mechanics. They are adapted for problems, therefore a bit different from original ones. Please use statements as formal documents.

Some problems have animated pictures. Please ensure that your browser supperts formats APNG or GIF.

Problem points will be standard for contests of Codeforces:
500-1000-1500-2000-2500.

Good luck!

UPD. The contest ended and ratings was recalculated.
:Winners:
1. KADR
2. neal
3. cerealguy
4. ivan.popelyshev
5. tourist

Editorial.

Read more »

 
 
 
 
  • Vote: I like it  
  • -7
  • Vote: I do not like it  

By Ripatti10 months ago, translation, In English

A naive solution works in O(nmk). This solution stores all the start positions into an array and next iterates over all commands and shifts positions in needed directions. After every move it checks that all positions lie on the exit cell.

This solution doesn't fit into time limits.

An author's solution speed up the naive solution with using of bit masks.

Read more »

 
 
 
 
  • Vote: I like it  
  • +13
  • Vote: I do not like it  

By Ripatti11 months ago, translation, In English

A div2. In this problem you can simulate the process. You can consider all minutes and in dependence by a color of a current cablecar decrease size of corresponding group of students G by min(|G|, 2), where |G| is size of the group. After that you should determine the first minute t in that all three groups of students will be empty. So t + 30 is an answer. This solution works in O(r + g + b).

Read more »

 
 
 
 
  • Vote: I like it  
  • +34
  • Vote: I do not like it  

By Ripatti11 months ago, translation, In English

Hello everyone!

I am an author of problems of today round. This round is for both divisions. There will be 7 problems, the first 5 of them are for the second division and the last 5 are for the first one.

About points of problems. Today they are nonstandard:
for div2: 500-1000-1500-2000-2000
for div1: 500-1000-1000-1500-2500
Be careful.

RAD helped me for preparing the round. Delinur translated statements into English.

Good luck ans have fun.

UPD.
 winners of the first division
1. peter50216
2. tourist
3. ACRush

winners of the second division
1. iamcs1983
2. zyx3d
3. seanwupi

Editorial.

UPD.
Unfortunately, in author's solution of priblem E some bug was found. We thanks participant LinesPrower for detection of it. Author's solution was updated and all solutions were rejudjed. Ratings will be recalculated for all participants excluding Egor and Jacob. We apologize for this incident.

Read more »

 
 
 
 
  • Vote: I like it  
  • +187
  • Vote: I do not like it  

By Ripatti13 months ago, translation, In English

A. You should count a number of vowels for every of three phrases. Next, you should compare this numbers with numbers 5, 7 and 5. If all is matched, answer is YES, otherwise answer is NO.

Author of problem is Ripatti.

Read more »

 
 
 
 
  • Vote: I like it  
  • +24
  • Vote: I do not like it  

By Ripatti13 months ago, translation, In English
Good evening.

I'm glad to welcome you on this Codeforces beta round.

Authors of today problemset are Ripatti (it is me) and Lepetrandr. it4.kp, MikeMirzayanov, RAD, Nerevar and dlevshunov helped in preparing the round. Delinur translated statements into English.

Good luck for all!

UPD
Winner is Neverauskas.
Editorial.

Read more »

 
 
 
 
  • Vote: I like it  
  • +64
  • Vote: I do not like it  

By Ripatti13 months ago, translation, In English
A. You can do exactly what is written in a statement. Only one pitfall in this problem is that room leader may have number of points less than zero.

Read more »

 
 
 
 
  • Vote: I like it  
  • +43
  • Vote: I do not like it  

By Ripatti13 months ago, translation, In English
Hello everyone!

I am an author of the today problemset. It is my third contest on Codeforces and the first one for div 1.

I thanks Artem Rakhov, Maria Belova, Pavel Kuznetsov and Mike Mirzayanov for help in preparing of this round.

Happy hacking!

Winner is tourist.
Editorial.

Read more »

 
 
 
 
  • Vote: I like it  
  • +183
  • Vote: I do not like it  

By Ripatti14 months ago, translation, In English
A. In this problem you can just do what is written in the statement. Let read all words. For each of them compute its length L, its the first and the last letter. If L > 10, output word without any changes, otherwise output the first letter, next L - 2 and finally the last letter.

Read more »

 
 
 
 
  • Vote: I like it  
  • +47
  • Vote: I do not like it  

By Ripatti14 months ago, translation, In English
Hello everyone!

I am an author of today problemset. It is my second round on Codeforces. I hope you will like this round like my first one:)

Good luck!

UPD
Winner is unicef.
Editorial.

Read more »

 
 
 
 
  • Vote: I like it  
  • +102
  • Vote: I do not like it  

By Ripatti15 months ago, translation, In English
A. This problem can be easily solved with the following algorithm. First, read names ans statuses of all crew members into an array. Next, iterate over the entire array 4 times. In the first pass output names of rats. In the second pass output names of women and children. In the third pass output names of men. Finally, in the fourth pass output the name of the captain.

Read more »

 
 
 
 
  • Vote: I like it  
  • +41
  • Vote: I do not like it  

By Ripatti15 months ago, translation, In English
Hello everyone!

I am problems' author of today round. I hope you will like this contest :)

I thank Artem Rakhov, Maria Belova and Dmitry Matov for help in preparing of the round.

Good luck!

UPD.
Winner is levlam.
Tutorial.

Read more »

 
 
 
 
  • Vote: I like it  
  • +91
  • Vote: I do not like it  

By Ripatti15 months ago, In Russian
На сайте http://www.azspcs.net/ завершился очередной контест.
Контест трехмесячный, однако на данный сайт я наткнулся всего несколько недель назад. Решил поучаствовать, дабы, так сказать, распробовать новый вид соревнований.

Read more »

 
 
 
 
  • Vote: I like it  
  • +13
  • Vote: I do not like it  

By Ripatti2 years ago, translation, In English
Author thanks adamax for translation this article into English.

Introduction
After Codeforces Beta Round #11 several participants expressed a wish to read something about problems similar to problem D of that round. The author of this article, for the purpose of helping them, tried searching for such information, but to his surprise couldn't find anything on the Internet. It is not known whether the search was not thorough or there's really nothing out there, but (just in case) the author decided to write his own article on this topic.

In some sense this article may be regarded as a tutorial for the problem D from Beta Round #11.

Read more »

 
 
 
 
  • Vote: I like it  
  • +22
  • Vote: I do not like it