Блог пользователя sidprasad

Автор sidprasad, 9 лет назад, По-английски

Hi Codeforces!

Programming Club, IIT Indore and Fluxus 2017 are proud to present, for the first time on Codeforces, our flagship event, Divide By Zero!

The contest is going to be held on Monday, 20th Feb at 9:35PM IST.

Prizes: Codeforces T-shirts for top 15 overall and top 15 in India.

Thanks to the following people for making this round possible:

There are 7 problems, and 2.5 hours to solve them. The points distribution will be updated later.

Fluxus is the annual techno-cultural festival of Indian Institute of Technology, Indore. It is a 3-day event and generally held in the month of February. Started in 2011, Fluxus is the largest college festival of central India.

Hope you guys enjoy the contest! See you on the leaderboard!

UPD: The scoring is 500-1000-1250-1750-2000-2250-2750.

UPD2: Thanks a lot everyone for your participation!

We hope you all enjoyed the contest. Yes, there were a few things we could've done better, and unfortunately the system was down for a while, We sincerely thank the CF team for dealing with it in the nick of time.

This was our first (of many, hopefully) contest on Codeforces. We request you to fill in this form with your feedback so that we can do better next time. Thank you!

The following users win T-shirts! Congrats!

Overall Top 15:

  1. y0105w49
  2. W4yneb0t
  3. V--o_o--V
  4. Merkurev
  5. anta
  6. I_love_Tanya_Romanova
  7. Endagorion
  8. BigBag
  9. HYPERHYPERHYPERCUBELOVER
  10. EvenImage
  11. natsugiri
  12. mnbvmar
  13. halyavin
  14. Shik
  15. Aeon

Indian Top 15:

  1. Sumeet.Varma
  2. rajat1603
  3. xorfire
  4. memset123
  5. animeshf
  6. akulsareen
  7. shubham1694
  8. alecsyde
  9. AnonymousBunny
  10. ajinkya1p3
  11. mohitbindal
  12. wittyskull
  13. chintu
  14. ajs97
  15. polingy

UPD3: Editorial

  • Проголосовать: нравится
  • +324
  • Проголосовать: не нравится

»
9 лет назад, скрыть # |
Rev. 2  
Проголосовать: нравится +3 Проголосовать: не нравится

Good luck !

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +1 Проголосовать: не нравится

Great.Looking forward to it.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

Cool! Must participate in. Thanks for contest

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +29 Проголосовать: не нравится

В предвкушении 400-го раунда, надеюсь будет что-то особенное

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +6 Проголосовать: не нравится

Hehe Now would be a fight because of the T-shirts)

Всё кароч, ща будет мясо из-за маечек)

»
9 лет назад, скрыть # |
 
Проголосовать: нравится -18 Проголосовать: не нравится

13 people worked to make this round !!

so it has many cartoons and long statements :D

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +11 Проголосовать: не нравится

Someone posted a photo on the last round's blog..About Pigeon Hole theory.. 13 writers made me remind of that :'|

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +3 Проголосовать: не нравится

It had better the T-shirts was for random people from 1..500(for example).Then there will be a chance to win it!!!

»
9 лет назад, скрыть # |
Rev. 2  
Проголосовать: нравится -36 Проголосовать: не нравится

...

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +9 Проголосовать: не нравится

It's not customary to ask if it's a rated, so I have to come up with different question...

"Prizes: Codeforces T-shirts for top 15 overall and top 15 in India."

Is it racist?

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +18 Проголосовать: не нравится

Well done! because you say thanks to MikeMirzayanov

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

So now codeforces is not just Russia, Spreading legs.

good work mike and team

»
9 лет назад, скрыть # |
Rev. 2  
Проголосовать: нравится +58 Проголосовать: не нравится

I don't know why, but I feel some math problems

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +36 Проголосовать: не нравится

Finally a contest with its time given in IST :D

No need to convert to IST from UTC :P

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

I hasn't had a T-Shirt before :'(

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

Can I register now? I forgot yesterday and now I am seeing it's Registration is completed!

»
9 лет назад, скрыть # |
Rev. 3  
Проголосовать: нравится -103 Проголосовать: не нравится

India is becoming popular day by day in terms of organizing programming contest in Codeforces.

  • »
    »
    9 лет назад, скрыть # ^ |
     
    Проголосовать: нравится -193 Проголосовать: не нравится

    YES !!! INDIA ROCKS !!! ALL OTHER COUNTRIES SUCK !!! :) :) :)

    इंडिया !!!!!!!!!!!!!!!!!!

    • »
      »
      »
      9 лет назад, скрыть # ^ |
       
      Проголосовать: нравится -158 Проголосовать: не нравится

      WHY ALL THIS DOWNVOTES !!! :( READ THIS BUTTHURT OTHER COUNTRIES !

      Its the contribution of Indians to every field known to men that makes India one of the greatest country of the world . In the words of other great personalities :

      Will Durant, American historian: "India was the motherland of our race, and Sanskrit the mother of Europe's languages: she was the mother of our philosophy; mother, through the Arabs, of much of our mathematics; mother, through the Buddha, of the ideals embodied in Christianity; mother, through the village community, of self-government and democracy. Mother India is in many ways the mother of us all".
      Mark Twain, American author: "India is, the cradle of the human race, the birthplace of human speech, the mother of history, the grandmother of legend, and the great grand mother of tradition. Our most valuable and most instructive materials in the history of man are treasured up in India only. "
      Albert Einstein, American scientist: "We owe a lot to the Indians, who taught us how to count, without which no worthwhile scientific discovery could have been made. "
      Max Mueller, German scholar: If I were asked under what sky the human mind has most fully developed some of its choicest gifts, has most deeply pondered on the greatest problems of life, and has found solutions, I should point to India.
      Romain Rolland, French scholar : "If there is one place on the face of earth where all the dreams of living men have found a home from the very earliest days when man began the dream of existence, it is India. "
      R.W. emerson, American Author: In the great books of India, an empire spoke to us, nothing small or unworthy, but large, serene, consistent, the voice of an old intelligence, which in another age and climate had pondered and thus disposed of the questions that exercise us.
      Hu Shih, former Ambassador of China to USA: "India conquered and dominated China culturally for 20 centuries without ever having to send a single soldier across her border. "
      Keith Bellows, National Geographic Society : "There are some parts of the world that, once visited, get into your heart and won't go. For me, India is such a place. When I first visited, I was stunned by the richness of the land, by its lush beauty and exotic architecture, by its ability to overload the senses with the pure, concentrated intensity of its colors, smells, tastes, and sounds... I had been seeing the world in black & white

      Some great facts about India: 1)Each and every 28 states and 7 union territories of India, have their own LANGUAGE, CLOTHING, CUISINE and LOOK.

      2)India alone has the highest number of languages in the world with more than 300 I guess.

      3)In India alone you'll find all types of food ranging from sweetest to most spicy food on Earth. I'm not talking about foreign cuisine or restaurants. Its the local food of different states.

      4)On this planet, you will notice that the highest number of religions present, are in India. More than 8-Christianity, Islam, Judaism, Hinduism, Jainism, Sikhism, Zoroastrianism, Buddhism.

      After reading all these facts , you might be convinced that India is a great country . If you are , you have clearly misunderstood what makes a country great . Its not the history that makes a country great . India is a barren naked land without its cultures, its colors, its religions. However, as a person cannot be deemed great for the clothes he wears; his shoes or hairstyle or the fragrance he chooses to spray over himself, I doubt if greatness should lie in the clothes of cultures, color or monuments India wears. Not only is such a statement highly propagandist, it deems other nations with perhaps equally diverse cultures, peoples and religions un-great. For greatness is a crown for the elite few.

      And for all its culture, its history, its religion, its minarets, its color, India like any other country is made of people. Human beings. Little pink creatures, with dark hearts. This is again not a license to greatness, because every country I know of, is made up of human beings.

      The man on the street, the rickshaw puller, the tobacco- paan seller, will easily enter into an animated debate on the issue of India’s greatness. To them, all the corruption, the famines (and the Rs. 3 cheques), the electricity shortages, the broken roads, the stinking sewers, peddled to them by their hindi dailies, are signs of a nation gone to the dogs, faltering and staggering and falling.

      But the same paan-wallah, the rickshaw puller, will glue themselves to any available radio set if India is playing hockey/ cricket; will talk in higher, happier tones of Sunita Williams, as if she were their blood sister; and celebrate the Indo-US nuclear deal (without being sure of its meaning). Thus is India great, for its people never give up hope. For all our rot and rust and famine and flood, we never stop believing in the Indian dream. Thus, we call her "Mother India" for its peoples are always expecting.

      In the end , its the people of India (except those corrupt politicians) who make this country great .

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +32 Проголосовать: не нравится

Hope there won't be cheaters :) Good luck everyone.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +13 Проголосовать: не нравится

Codeforces judging system seems down! God knows what will happen! :(

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +2 Проголосовать: не нравится

Good luck to everyone

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

I hope to redeem myself from the previous contest. :)

»
9 лет назад, скрыть # |
 
Проголосовать: нравится -22 Проголосовать: не нравится

Will it be a rated one? I did not see u guys mentioning it anywhere.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +63 Проголосовать: не нравится

"largest college festival of central India" — every central India college fest claims this :P

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

I hope it's good contest

»
9 лет назад, скрыть # |
 
Проголосовать: нравится -16 Проголосовать: не нравится

The points distribution shows that the problems don't have gap in their complexity! Good!

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +3 Проголосовать: не нравится

feel sleepy at midnight zzz~

»
9 лет назад, скрыть # |
Rev. 2  
Проголосовать: нравится +78 Проголосовать: не нравится

Rating prediction for this contest could be found here (after contest begins)

Extensions:

About CF-Predictor

Good luck & high rating to everyone!

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

damn . cant understand problem c again :|

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +5 Проголосовать: не нравится

too easy I forgot to submit !!

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

Why the solution of number B is in queue for a long time????

»
9 лет назад, скрыть # |
Rev. 3  
Проголосовать: нравится -18 Проголосовать: не нравится

admit it
great contest
UPD : LOL the judge system has downed since I wrote this comment
but despite of all these issues, I think the problems are very interesting and the problem statements are very clear

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +31 Проголосовать: не нравится

Judge system down :(

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

It seems like queue of hack is very big! Submitted about 8 minutes ago , Still in queue!

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

Queue :(

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +8 Проголосовать: не нравится

10 minutes in queue.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится -15 Проголосовать: не нравится

Seems like unrated round :(

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +35 Проголосовать: не нравится

Whatever Happens!! I want to see ratings changed!! :P

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

Just after the announcement on 'C' judge system went down! Submission of 'C' everywhere!!

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +49 Проголосовать: не нравится

Is the system divided by zero?

Cf get runtime error xD

»
9 лет назад, скрыть # |
 
Проголосовать: нравится -19 Проголосовать: не нравится

solutions are in queue for a very long time . Contest might become unrated.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +10 Проголосовать: не нравится

Почему раунд рейтинговый?

  • »
    »
    9 лет назад, скрыть # ^ |
     
    Проголосовать: нравится +20 Проголосовать: не нравится

    Наверное, потому что неприятность случилась в самом конце контеста, а для тех на кого она повлияла серьезно, возможно, сделают индивидуально нерейтинговый раунд, как уже было когда-то ранее.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

Сейчас бы 700+ отправок в очередь и раунд рейтинговым оставить...

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +31 Проголосовать: не нравится

The contest should be unrated.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +4 Проголосовать: не нравится

please extend the time of contest

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +3 Проголосовать: не нравится

either time should be extended or the contest should be made unrated!

»
9 лет назад, скрыть # |
 
Проголосовать: нравится -9 Проголосовать: не нравится

Not only the judging system ... The whole site is maybe slowed down :( Any page is taking near 3-4 minutes to load.. My Internet Speed is ok.. :(

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +71 Проголосовать: не нравится

Make it unrated!! 25 min wait times are unreasonable.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится -7 Проголосовать: не нравится
»
9 лет назад, скрыть # |
 
Проголосовать: нравится -6 Проголосовать: не нравится

Some people for some reason do not have access to debug tools other than codeforce which went down for an hour. Rated, seriously?

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +5 Проголосовать: не нравится

Я, конечно, рискую словить много минусов, но всё-таки считаю что раунд должен быть рейтинговым. Не знаю как у остальных, у меня дольше 3х минут в очереди не было задач )

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

:( прям когда начелся раунд интернет отключился (( заработал до 20 конца раунда ) хорошо что хоть 1 задачу решил :)

»
9 лет назад, скрыть # |
Rev. 2  
Проголосовать: нравится +5 Проголосовать: не нравится

In Problem C I used the trivial solution :D I do the operations until I find that my array is repeated :D

Will this exceed the Time limit in some cases ? :p

  • »
    »
    9 лет назад, скрыть # ^ |
     
    Проголосовать: нравится 0 Проголосовать: не нравится

    If you are checking for repetition, each of 'k' iterations could take O(n) time for comparison and O(n*log(n)) for sorting. So if the array doesn't repeat then there is a good chance that the solution would timeout.

»
9 лет назад, скрыть # |
Rev. 2  
Проголосовать: нравится +29 Проголосовать: не нравится

RIP those that didn't saw the unusual time limit on Problem C.

It took me 2 hours to realize that (+ xi <= 1000) and then write solution with O(k*1000)

»
9 лет назад, скрыть # |
Rev. 2  
Проголосовать: нравится +162 Проголосовать: не нравится

So many times someone said (Swistakk for example) that scoring should form something closer to a geometric progression. My G submitted in last minutes after two WA's is worth 912 points. Awesome. I hope that my B will pass because it's worth more.

Was points loss adjusted to a longer contest? If not, it only made things worse.

EDIT: fortunately my B passed

  • »
    »
    9 лет назад, скрыть # ^ |
     
    Проголосовать: нравится +5 Проголосовать: не нравится

    Points loss was the 2:00 formula for a 2:30 + 0:10 contest. Did asking that really take less effort than subtracting 2 numbers?

    • »
      »
      »
      9 лет назад, скрыть # ^ |
       
      Проголосовать: нравится +5 Проголосовать: не нравится

      Subtracting what 2 numbers? I still don't know how to easily say if points loss was adjusted.

      • »
        »
        »
        »
        9 лет назад, скрыть # ^ |
         
        Проголосовать: нравится 0 Проголосовать: не нравится

        In a 2:00 contest, a task worth x points should lose x/250 points per minute.

        Check what minute you submitted, how many points below the maximum you are (not counting points lost to wrong submissions) and discover that you indeed lost x/250 per minute.

        • »
          »
          »
          »
          »
          9 лет назад, скрыть # ^ |
           
          Проголосовать: нравится +5 Проголосовать: не нравится

          Why should I know/remember that x/250 formula? And we're talking about dividing here (or at least multiplying) so things become harder than just subtracting ;p

          • »
            »
            »
            »
            »
            »
            9 лет назад, скрыть # ^ |
             
            Проголосовать: нравится -17 Проголосовать: не нравится

            You should remember it because if you did, you could have predicted your score for G (and maybe hacked instead) instead of whining after the contest.

            Disclaimer: I agree that this is a bad mechanic and should be changed.

            Disclaimer 2: Solving G is probably a more fun and productive use of your time than hacking, unless you just want rating.

            • »
              »
              »
              »
              »
              »
              »
              9 лет назад, скрыть # ^ |
              Rev. 2  
              Проголосовать: нравится 0 Проголосовать: не нравится

              I don't have to remember it because on the problem page I can see (on the right side) how many points I would get submitting right now. I knew during solving that I won't get much. It was still an optimal strategy after hacking — I have read all solutions to A in my room and hacked many of them. Following your logic: you should find me on the leaderboard and see that before arguing.

              My ranting has goal: organizers should use better scoring and should always (?) adjust scoring. It will make contests better.

              • »
                »
                »
                »
                »
                »
                »
                »
                9 лет назад, скрыть # ^ |
                 
                Проголосовать: нравится -15 Проголосовать: не нравится

                You should wait for systests to finish before mentioning the leaderboard.

                • »
                  »
                  »
                  »
                  »
                  »
                  »
                  »
                  »
                  9 лет назад, скрыть # ^ |
                   
                  Проголосовать: нравится +10 Проголосовать: не нравится

                  Why? I got TLE in G and my hacks weren't canceled. Which of my comments makes less sense now?

                • »
                  »
                  »
                  »
                  »
                  »
                  »
                  »
                  »
                  9 лет назад, скрыть # ^ |
                   
                  Проголосовать: нравится -8 Проголосовать: не нравится

                  The statement that solving G is better than trying to get even more hacks.

                  Of course, arguing based on 1 data point isn't very convincing, I'm just shitposting for the sake of shitposting.

                • »
                  »
                  »
                  »
                  »
                  »
                  »
                  »
                  »
                  9 лет назад, скрыть # ^ |
                  Rev. 2  
                  Проголосовать: нравится 0 Проголосовать: не нравится

                  I think we don't agree about the definition of "optimal strategy" in a case when a player (participant in this case) doesn't have full information about the game.

                  EDIT: Also, congratulations for your place. Let's say that your strategy turned out to be more optimal. What an ugly sentence I've just created.

  • »
    »
    9 лет назад, скрыть # ^ |
     
    Проголосовать: нравится +86 Проголосовать: не нравится

    ranting part 2

    I think that tricky tests with f = 0 or w = 0 in 768F - Barrels and boxes should be included in pretests. You can't expect people to hack this problem because in most of rooms at most 1 person solves such a problem. So you just give WA's to all people that miss that thing. And for many it was misreading the statement (understanding that both f and w are positive), not forgetting about corner case.

    Let me also say something positive: I liked 768G - The Winds of Winter.

  • »
    »
    9 лет назад, скрыть # ^ |
    Rev. 2  
    Проголосовать: нравится +35 Проголосовать: не нравится

    Hello not adjusted drain, my old friend. I've come to butthurt about you again.

    I can't believe that not adjusted drain and bad scoring is still a thing. Completely trivial D, E worth 1750 and 2000 points and G worth 2750, sounds legit.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +10 Проголосовать: не нравится

Could someone please explain how to solve B? Thanks.

  • »
    »
    9 лет назад, скрыть # ^ |
    Rev. 3  
    Проголосовать: нравится +5 Проголосовать: не нравится

    Notice that, x will produce an array of length 2log(x)⌋ + 1 - 1. Let's call this number len(x)

    I solved it recursively,

    f(x, l, r, s) = number of ones at the intersection between the intervals [s, s + len(x) - 1] and [l, r]

    If [s, s + len(x) - 1] is totally contained in [l, r] then the answer is x. If they don't intersect, the answer is 0.

    Otherwise, f(x / 2, l, r, s) + f(xmod2, l, r, s + len(x / 2)) + f(x / 2, l, r, s + len(x / 2) + 1)

    Answer is f(x, l, r, s = 1)

    I think this solution is too complicated, though :(

  • »
    »
    9 лет назад, скрыть # ^ |
    Rev. 2  
    Проголосовать: нравится 0 Проголосовать: не нравится

    Divide n by 2 until it is 0 and put that in an array in ascending order.

    You can see a pattern generated by the number and the final set.

    Take the index of one 1/0 in the list. Then take the highest power of two that divides that index. The expoent of the power will be exactly the index of the corresponding number that generated it in the array that we built. Therefore, if the number in the array is even, it will be 0, if it is odd, it will be 1.

    Thus, we can just iterate from l to r, checking the powers of two, and adding 1 or 0 to a counter according to the prebuilt array.

    i.e. suppose n is 17

    the array built will be 1 2 4 8 17

    suppose l is 12 and r is 16

    12 is divided by 4, which is 2^2, the index 2 in the array is 4, which is even, so the position 12 in the list is 0

    13 is divided by 1 which is 2^0, the index 0 in the array is 1, which is odd, so the position 13 in the list is 1

    14 is divided by 2 which is 2^1, the index 1 in the array is 2, which is even, so the position 14 in the list is 0

    15 gives the same as 13 (and actually every odd index)

    16 is divided by 16 which is 2^4, the index 4 in the array is 17, which is odd, so the position 16 in the list is 1 and so on.

    I find that this is the simplest way to solve the problem (my solution was 17 lines long). Unfortunately my solution received Runtime Error because I forgot to test when n = 0.

    Expected complexity O(log N + 50 * (R — L))

    code
»
9 лет назад, скрыть # |
Rev. 3  
Проголосовать: нравится 0 Проголосовать: не нравится

problem B why i get TLE ..complexity is O((r-l) LOGN * LOG N ) ?

r-l <=10e5

here

»
9 лет назад, скрыть # |
Rev. 2  
Проголосовать: нравится +212 Проголосовать: не нравится

read G

persistent dynamic online balanced link-cut tree decomposition

hack greens instead

  • »
    »
    9 лет назад, скрыть # ^ |
    Rev. 3  
    Проголосовать: нравится +37 Проголосовать: не нравится

    I used a segment tree of multisets only.

    For each vertex we want to know the list of sizes of trees that will remain after this vertex is cut. Let BIG and SMALL denote the biggest and smallest of them. It's enough to consider moving some subtree of BIG into SMALL. It's optimal to make the size of moved subtree of size as close to (BIG-SMALL)/2 as possible. Let's see how to do it.

    We compute preorders and we build a segment tree of multisets. For any interval we want to know the set of sizes of subtrees with preorder in this interval. In O(log2) we can ask a structure about a size closes to some value.

    There is one hard thing left: if BIG turns out not a child of our vertex but its parent and everything above, then we should differently consider subtrees starting from somewhere on the path from our current vertex to the root. If the size of subtree was X initially and our current vertex is v then cutting and moving that subtree moves size X - a. So we need a second segment tree of multisets that will store sizes of subtrees that start somewhere on a path from the current vertex to the root. As we move deeper in a tree, we should remove elements from the first structure and insert them in the second one.

    EDIT: I got TLE. The complexity is with not so small constant factor. Maybe it can be implemented slightly better.

  • »
    »
    9 лет назад, скрыть # ^ |
    Rev. 2  
    Проголосовать: нравится +87 Проголосовать: не нравится

    My reaction : https://ibb.co/i703Yv

»
9 лет назад, скрыть # |
Rev. 2  
Проголосовать: нравится +27 Проголосовать: не нравится

Was B really hard or was it just me :(

edit — just a stupid mistake :/

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

What's the matter with last contests? Bug, bug everywhere :(

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

Problem E get WA on pretest 17, can't find the bug..

  • »
    »
    9 лет назад, скрыть # ^ |
     
    Проголосовать: нравится 0 Проголосовать: не нравится

    How do you solve it?

    • »
      »
      »
      9 лет назад, скрыть # ^ |
       
      Проголосовать: нравится 0 Проголосовать: не нравится

      Just some game theory about NIM.

      • »
        »
        »
        »
        9 лет назад, скрыть # ^ |
         
        Проголосовать: нравится +3 Проголосовать: не нравится

        What do you do with NIM? I tried to think of something but failed.

        • »
          »
          »
          »
          »
          9 лет назад, скрыть # ^ |
           
          Проголосовать: нравится 0 Проголосовать: не нравится

          just do brute-force and fits the TL, but I don't know why I fail pretest 17..

          I use following state definition and brute force to calculate every dp[i][0]
          map<ll, int> dp[80];

          • »
            »
            »
            »
            »
            »
            9 лет назад, скрыть # ^ |
            Rev. 3  
            Проголосовать: нравится +6 Проголосовать: не нравится

            I found a pattern.
            1 repeat 2 times
            2 repeat 3 times
            3 repeats 4 times and so on..
            so grundy[1]=grundy[2]=1
            grundy[3]=grundy[4]=grundy[5]=2
            grundy[6]=grundy[7]=grundy[8]=grundy[9]=3... and so on.

            Edit : Sharing code, just in case someone wanted to see. It took about 8 secs on my pc.

            generator
          • »
            »
            »
            »
            »
            »
            9 лет назад, скрыть # ^ |
             
            Проголосовать: нравится 0 Проголосовать: не нравится

            You can just do brute-force to figure out that the Grundy numbers for the starting positions for each pile are 1, 1, 2, 2, 2, 3, 3, 3, 3... Then you won't need to slow your solution down by doing brute force.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +241 Проголосовать: не нравится
if(n>2){

int lol=rand()%2;

if( lol%2 ) printf("NO\n");
else printf("YES\n");

return 0;

}   

get accepted on pretests in E ))))))))))))00000000)))))))))0
http://mirror.codeforces.com/contest/768/submission/24852367

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

How to solve E? I could not find out the Grundy numbers of the states?

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +13 Проголосовать: не нравится

the slow of system was to show as what's happening when you divide by zero :D

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +71 Проголосовать: не нравится

For F, I just realized that I misread the conditions, so in particular, if there are no wine barrels, it seems like the probability is 1 (since there is no stack with height <= h, the condition is trivially satisfied). I printed zero, since I misread it as there is at least one stack, and all stacks have height > h.

I'm surprised that this case isn't in the pretest. Also, I'm not sure I like having the condition that there may be zero wine barrels or food barrels since this is hardcoding special cases and not really related to solving the main problem.

  • »
    »
    9 лет назад, скрыть # ^ |
     
    Проголосовать: нравится +5 Проголосовать: не нравится

    I have the same bug, I misread it as "It is guaranteed that he has at least one food box AND at least one wine barrel." :-(

    • »
      »
      »
      9 лет назад, скрыть # ^ |
       
      Проголосовать: нравится +40 Проголосовать: не нравится

      Same here. I was wondering why F is F, cause it seemed to be too easy for one of the hardest problems. Now I see that the trickiest part of the problem was "read the statement carefully and do not forget to handle corner cases" )

  • »
    »
    9 лет назад, скрыть # ^ |
     
    Проголосовать: нравится +63 Проголосовать: не нравится

    I'm much more stupid. I asked a question:

    "It is guaranteed that he has at least one food box or at least one wine barrel."
    is it equivalent to saying that 1 ≤ f, w?
    I'm asking because there is 0 ≤ f, w just before that

    I got answer: It's equivalent to 1<=f+w

    ... and I misread that answer and understood 1 <= f, w

    ;_;

  • »
    »
    9 лет назад, скрыть # ^ |
     
    Проголосовать: нравится +6 Проголосовать: не нравится

    I was aware of that case and I hoped to hack someone. Unfortunately noone else submitted this problem in my room.

  • »
    »
    9 лет назад, скрыть # ^ |
    Rev. 2  
    Проголосовать: нравится +45 Проголосовать: не нравится

    More than 80 submissions failed system test because of this reason. :( And there are about 120 accepted submissions!

    It seems like authors are trying to decrease the number of accepted submissions for last problems by excluding special cases from pretests, instead of adding harder problems!

    • »
      »
      »
      9 лет назад, скрыть # ^ |
       
      Проголосовать: нравится -26 Проголосовать: не нравится

      ...

      Problem is as hard as many people are able to solve it (the more people can solve it, the easier the problem).

      It does not matter whether you almost solved the problem but you missed a special case or you did not have any idea how to solve it (no partial scores in codeforces — I recommend Hackerrank).

      The fact that almost nobody else in the room is not solving it and can't hack the solution, does not matter. You should think of all the cases upfront, before even submitting it.

      If you did not think of all the cases, you fail the problem. If it was a full feedback contest, then you would see the results during the contest. I totally do not understand your concerns.

      • »
        »
        »
        »
        9 лет назад, скрыть # ^ |
         
        Проголосовать: нравится +13 Проголосовать: не нравится

        A problem is what is said in its statement. Weak test data doesn't make it easier, and weak pretests doesn't make it harder.

        "Problem is as hard as many people are able to solve it."

        I agree. But we have different opinions about "solving" a problem!

»
9 лет назад, скрыть # |
Rev. 2  
Проголосовать: нравится +144 Проголосовать: не нравится

If feel this contest simply ... ought to be unrated. Nearly half the contest was feedback-less and the last 2 problems simply don't deserve their place as F and G for a division combined. I really appreciate the problem setters' efforts, but still.

Edit. As geniucos told me earlier, this was more of a Div2 + Div1 contest than a Div1 + Div2.

  • »
    »
    9 лет назад, скрыть # ^ |
    Rev. 2  
    Проголосовать: нравится +7 Проголосовать: не нравится

    Actually I said Div2 — Div1 (but your comment is not far anyway) as last div2 contest seemed to be harder than this one. Rated or unrated, one thing is for sure: the contest could hardly be regarded as good for div2 only, let alone a div1 + div2.

  • »
    »
    9 лет назад, скрыть # ^ |
    Rev. 2  
    Проголосовать: нравится +10 Проголосовать: не нравится

    I also think so,A-F implementation only,G didn't read.And i'm only violet.

  • »
    »
    9 лет назад, скрыть # ^ |
    Rev. 2  
    Проголосовать: нравится +39 Проголосовать: не нравится

    Well, feedback-less problem is a good reason to make a contest unrated, but its difficulty is not.

    • »
      »
      »
      9 лет назад, скрыть # ^ |
       
      Проголосовать: нравится +49 Проголосовать: не нравится

      It was just a second reason (even though it shouldn't be required as you had to wait for up to 20 minutes to get the feedback for one of your submissions). From other point of view, the quality of problems and pretests was the lowest I've seen lately (or, actually, ever) in a CF round. I just can't believe that E was solved by 567 people and half of the sources on F failed on a case in which W or H is 0 (which of course was not part of pretests). How could the assessment of the difficulty of the problems be so far from the reality?

      • »
        »
        »
        »
        9 лет назад, скрыть # ^ |
        Rev. 2  
        Проголосовать: нравится +38 Проголосовать: не нравится

        Also, I still can not fully understand why did they have to express a statement about precision in such an odd manner in D. Saying eps < 10 - 7 implies picking eps = 0 would have been valid, too, rendering the first statement useless to begin with.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +41 Проголосовать: не нравится

In problem F, is there any way to handle the case when q is divisible by 1e9+7?

»
9 лет назад, скрыть # |
Rev. 2  
Проголосовать: нравится -30 Проголосовать: не нравится

Good problem-set and a well balanced contest imo. (Although it might have been on the easier side for Div 1 contestants)

Failed to calculate the Grundy Number for E question though. How is it calculated?

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +19 Проголосовать: не нравится

I just screwed up this round but this might be the last pretest-passed submission. Cool

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

During the contest I (because of rushing and skipping the details) was solving such version of F: A configuration is good if any pile of wine has > h boxes. Is it still solvable in faster than O(N^2) time?

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

Does somebody know what pretest 4 on problem D was?

I've looked through other participants code,but the main ideea was the same.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +25 Проголосовать: не нравится

Should I cry now or later ?

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

For Problem F, when f or w equals to 0, as a result ,p equals to 0 too.And how to calculate the inverse of 0 under mod 1e9+7?

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +16 Проголосовать: не нравится

Just a little feedback from me. I liked all of the problems, I think they are all pretty nice. But weren't they way too easy (at least up to F, didn't read G)? I know I wasn't among the fastest solvers but still, I read E early and solved it quite fast IMO. Also, I knew how to solve F almost immediately after reading it, bad that I read it too late. But anyway, difficulty is a relative term, depending on people and types of problems. So, nice round, thanks :)

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +7 Проголосовать: не нравится

Is problem E's solution the same as nim problem? I saw some codes pass the pretest doing the same thing as the nim

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

please Explain why i got TLE ?

problem B ..complexity is O((r-l) LOGN * LOG N ) ? r-l <=10e5 Here

»
9 лет назад, скрыть # |
Rev. 3  
Проголосовать: нравится 0 Проголосовать: не нравится

What was the approach for D? I computed the log of numerator and denominator of http://math.stackexchange.com/a/1007107/115535 . Then binary search till the desired n, number of days, is obtained. But could not pass the pretests!

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +1 Проголосовать: не нравится

is supposed to TLE in B?

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

In problem C, if k is even nothing (besides sorting) in array won't be changed yes? If I'm wrong please correct me.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +91 Проголосовать: не нравится

I think main tests of problem D are too weak.

If k = 2 and p = 1000, the answer is 2 (probability is 1/2, which is greater than )

However, some source code (example: 24838082) outputs 3 but passed main tests.

  • »
    »
    9 лет назад, скрыть # ^ |
     
    Проголосовать: нравится +37 Проголосовать: не нравится

    I can't believe that k = 1 and k = 2 are not included. I think they should add those into the tests and rejudge before the ratings are released.

    • »
      »
      »
      9 лет назад, скрыть # ^ |
       
      Проголосовать: нравится +26 Проголосовать: не нравится

      Obviously they updated the ratings without rejudging. Contest authors these days tend to ignore comments from the community.

    • »
      »
      »
      9 лет назад, скрыть # ^ |
       
      Проголосовать: нравится +12 Проголосовать: не нравится

      Adding tests after the contest leads to strange situations. Should people be afraid to post "hah, my solution is wrong for this test: ..."? And what about solutions with hashes? Many solution can be hacked once you see it.

      • »
        »
        »
        »
        9 лет назад, скрыть # ^ |
         
        Проголосовать: нравится +19 Проголосовать: не нравится

        This case is obviously different from hashing. We are talking about tests that should have been included when the problem is prepared.

        • »
          »
          »
          »
          »
          9 лет назад, скрыть # ^ |
          Rev. 3  
          Проголосовать: нравится +15 Проголосовать: не нравится

          It's impossible to define a clear border — to say when tests should be added. I used to have the same opinion you have now. After many conversations and some thinking I changed my mind. Contest have clear rules: organizers prepare tests and your task is to pass them. You should be able to solve all valid tests but this is not what you get AC for. You get AC for passing tests prepared by organizers. Sometimes it allows to squeeze some too slow solution or get AC with an incorrect one — but judging is automatic and everybody is equal.

          EDIT: But ofc. I agree that tests should be strong in the first place and it's organizers' responsibility. Though I failed that task many times myself so I'm trying not to be very harsh to someone who did the same :D

          • »
            »
            »
            »
            »
            »
            9 лет назад, скрыть # ^ |
             
            Проголосовать: нравится +26 Проголосовать: не нравится

            I agree that tests should not be added if it is ACM or IOI format where contestants get their results live, or if the points are given per case like in HackerRank. But I don't think that's an issue in Codeforces because the contestants well know that there will be system tests.

          • »
            »
            »
            »
            »
            »
            9 лет назад, скрыть # ^ |
             
            Проголосовать: нравится 0 Проголосовать: не нравится

            Regarding the hashing problems, I agree that tests on hacking some hash functions should not be added in normal circumstances, as hashing functions can usually be hacked once you see it. So it is enough for the organizers to prepare cases that can reject the solutions that are wrong because of other stuffs.

            As you mentioned, organizers should be responsible to prepare strong tests. And it is obvious that corner cases should be regarded as part of strong tests as it is one of the contestants' goals to figure them out.

            If the tests are too weak(as mentioned by HYPERHYPERHYPERCUBELOVER), there are three main reasons that we should add tests in my opinion:

            1. As mentioned by microtony, adding tests after contest under Codeforces format do not create any unfair situations as those solutions still passed pretests. Contestants can still regard the new tests included in the System Test.
            2. It is organizers' responsibility to include such tests before the contest. So when those cases are not included, still, it is their responsibility to include them afterwards. Otherwise, organizers can be excluded from adding strong tests as they have no consequences even if they don't do so.
            3. It is unfair to those who have handled those corner cases if stronger tests are not included and added. Contestants who have handled corner cases should be ranked higher than those who have not. And moreover, it is much more important to guarantee so under contests with prizes as these may affect the ranking.

            I'm sorry if i wrote too long, but some of the recent contests were facing similar issues which lead me to think seriously.

            • »
              »
              »
              »
              »
              »
              »
              9 лет назад, скрыть # ^ |
               
              Проголосовать: нравится +17 Проголосовать: не нравится

              I understand reasons in favor of your opinion. You must understand reasons against it.

              Do you want a situation when after a contest people stress test solutions of others and try to break them, to move one place up? Someone will have to decide if a test should be added indeed, while it's impossible to clearly say what is a corner case and obviously should be added and what is not.

              still, it is their responsibility to include them afterwards

              ok, they can do it for upsolving

              It is unfair to those who have handled those corner cases if stronger tests are not included and added

              But they got AC and in the long run caring about corner cases gives better places obviously.

            • »
              »
              »
              »
              »
              »
              »
              9 лет назад, скрыть # ^ |
               
              Проголосовать: нравится 0 Проголосовать: не нравится

              It is possible that if the authors had come up with these tests, they would've included them in pretests. If I was an author, I would definitely do this. In this case it would've affected the competition in other way, so adding them now is not fair.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +104 Проголосовать: не нравится

G with 978 points :(

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +2 Проголосовать: не нравится

Editorial Please !!

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +6 Проголосовать: не нравится

Can some one explain the logic of 3rd question?

  • »
    »
    9 лет назад, скрыть # ^ |
     
    Проголосовать: нравится 0 Проголосовать: не нравится

    problem c look at the constraints 0<=ai<=1000 and 0<=x<=1000 , that means you will have at most 1001 distinct numbers in the initial array . and after taking xor with number you can maximum number with with all the 9 bit set .

    Fact 1: A^X=B , B^X=>A Maintain the count of each number arr[K][number]=count , after K operations . so when you are taking xor with i , that means you are taking roughly count/2 numbers and changing it to x^i . That means roughly count/2 element count increase for x^i .

    as K will be very huge and you make state for odd and even operations . - See code Solution

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +10 Проголосовать: не нравится

Seems that Problem E requires submitting a table, or your program needs to have a small constant. My program uses about 2.5s to calculate all the answer, which gives me confidence to submit. Then got TLE for big N only because N is very big :(

Constant... Constant... Constant...

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +5 Проголосовать: не нравится

Why did so many F's failed systests? I can't see any kind of corner case

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +14 Проголосовать: не нравится

Practice season please.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

I guess that without assert my B would be AC :/ Listen me my dear friends, don't use asserts on cp, just don't. :D

»
9 лет назад, скрыть # |
Rev. 2  
Проголосовать: нравится +7 Проголосовать: не нравится

Sorry for the error.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

I messed up this contest...a silly mistake in problem A..(instead of i--,i was doing i++) . I messed up last contest also...was declaring array of size 10^5 instead of 2*10^5 for problem A. What is happening with me?

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +14 Проголосовать: не нравится

When can we upsolve?

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +104 Проголосовать: не нравится

[Problem D] Just curious, what did "the probability of (...) is at least , where ε  <  10 - 7 mean?

Assuming that our task was to find the minimum number of days after which the probability of collecting all the orbs is larger than : did you check if for all the feasible inputs the answer will not change when the float precision errors are taken into account? For example, the answer could have changed when pi = 500 ± 10 - 200 and our solutions (DP based on some floating-point calculations) wouldn't even notice that.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится -16 Проголосовать: не нравится

for B i used the same approach but he got ACC and i got TLE ? i use Java and he uses C++ .

c++

JAVA

THAT'S NOT FAIR ?

»
9 лет назад, скрыть # |
Rev. 2  
Проголосовать: нравится 0 Проголосовать: не нравится

problem D ->

http://mirror.codeforces.com/contest/768/submission/24841958 Why do i get wrong answer on pretest 4 , i used dp solution ??? on my machine the code outputs the correct answer , also on cpp.sh.

can some1 figure out what is wrong with my code ???

ive compiled with gcc 5.4.1 and also with 6.2.0 same result (the correct result) thank you

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +25 Проголосовать: не нравится

please add problems to practise.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +66 Проголосовать: не нравится
balanced
»
9 лет назад, скрыть # |
 
Проголосовать: нравится +1 Проголосовать: не нравится

I have an O(logN) solution for B. We can observe that the sum of number of ones in the expansion of n is n. f(n,l,r)=f(n,1,r)-f(n,1,l-1) and so now to calculate f(n,1,r) we can see where exactly r lies. Let M be the mid point of the expansion. If r lies to the left, we have a single call to f(n/2,1,r). Else we add n/2, n%2 and f(n/2,1,r-m), which is the remaining sum.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +5 Проголосовать: не нравится
Sad story here
»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

http://opencup.ru/files/oc7/gp2/problems.pdf

Тут задачка F идентична сегодняшней D, но с чуть более сильными ограничениями.

»
9 лет назад, скрыть # |
Rev. 5  
Проголосовать: нравится +3 Проголосовать: не нравится

Can anyone explain the logic in the following code? I am not getting the point why k%1024 is taken? Please help me out. Problem C. Accepted solution link: http://mirror.codeforces.com/contest/768/submission/24852093

Accepted code:

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main()
{
int n,k,x;
vector <int> v;
cin>>n>>k>>x;
for(int i=0;i<n;i++)
{
    int a;
    cin>>a;
    v.push_back(a);
}
if(k>1024)
    k=k%1024;
for(int j=0;j<k;j++)
{
    sort(v.begin(),v.end());
    for(int i=0;i<n;i++)
       if(i%2==0)
         v[i]=v[i]^x;
}
sort(v.begin(),v.end());
cout<<v[v.size()-1]<<' '<<v[0]<<endl;
return 0;

}

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

After an hour of meditation I still cannot understand the following solution: 24828716.
Could someone, please, explain it? =)

  • »
    »
    9 лет назад, скрыть # ^ |
    Rev. 5  
    Проголосовать: нравится 0 Проголосовать: не нравится

    First he's reversing the bit-pattern of 'n'.

    In the final generated sequence, the i'th number corresponds to the k'th most significant bit (MSB) of input 'n' (where 'k' is the position of least significant 1 in binary representation of i).

    Ex: n = 5 (101 in binary)

    generated sequence 's'

    s : 1 0 1 1 1 0 1

    i : 1 2 3 4 5 6 7

    k : 1 2 1 3 1 2 1

    i to k, for i = 6: 6 = 110 in binary, the least significant 1's position (k) in 'i' is 2

    similarly for i = 7, k = 1;

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +37 Проголосовать: не нравится

My collection is complete!

»
9 лет назад, скрыть # |
Rev. 2  
Проголосовать: нравится 0 Проголосовать: не нравится

In C problem , i supposed that the cycle is small. But how should I prove that the length of this cycle is smaller than 100 ? :) my accepted code :

http://mirror.codeforces.com/contest/768/submission/24855247 edited

»
9 лет назад, скрыть # |
Rev. 3  
Проголосовать: нравится +6 Проголосовать: не нравится

Someone knows why this n*log(n) solution for problem C gets AC? http://mirror.codeforces.com/contest/768/submission/24855627 Weak test cases?

»
9 лет назад, скрыть # |
Rev. 2  
Проголосовать: нравится -12 Проголосовать: не нравится

Unsual time and variable limits on problem c! :|

»
9 лет назад, скрыть # |
Rev. 3  
Проголосовать: нравится 0 Проголосовать: не нравится

Hey, can someone tell me: There has been several instances where using a memo table and solving a dp problem recursively has gotten me TLE while an iterative solution done extremely similar would get AC. Is there something inherently wrong or restricting with recursive dp or is it something I'm doing wrong?

Here's an example from this contest:

In contest recursive: 24838211

Out of contest iterative: 24854866

There is a noticeable difference in the in contest one as I was using binary search on the day, but I don't think that was what was getting TLE, if it was please tell me. Thank you!

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +5 Проголосовать: не нравится

It's a pity I don't see my id in homepage. Hope to add top 5 in div2 to announcement. :)

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

I don't know why my code outputs too many answers in test case 7. Please tell me the reason! http://mirror.codeforces.com/contest/768/submission/24859236

»
9 лет назад, скрыть # |
 
Проголосовать: нравится 0 Проголосовать: не нравится

HELPPP PLEASE — Im getting CRAZY/NUTS/COCONUTS

REGARDING PROBLEM C, I submited three identical solutions but with different results wrong , right1 and right2. The only diference is the vector size (1025, 1024 and 1500 respectively). all should work since the probolem uses only the first 1024 slots.

I suppose it is somekind of undefined behaviour, can someone please help me? this is driving me crazy...

  • »
    »
    9 лет назад, скрыть # ^ |
     
    Проголосовать: нравится +1 Проголосовать: не нравится

    Only the 1024 version should be AC. You have a for loop: for(int i = 0; i<v[ATUAL].size(); i++){. If you have 1025 in your code, the last value of i will be 1024. Two lines later, you access v[OUTRO][i^x], which will be out of bounds if x > 1.

»
9 лет назад, скрыть # |
 
Проголосовать: нравится +6 Проголосовать: не нравится

Did anyone get their T-Shirts? I haven't received mine yet...