allllekssssa's blog

HackerRank HourRank 1
By allllekssssa, history, 9 years ago, In English

Hello Codeforces community !

I am glad to announce the first HackerRank HourRank round! The contest will be held on 15th October 2015 at 15:00 UTC. You can sign up for the contest here. Top 10 winners on the leaderboard will receive a HackerRank T-Shirt.

Problems have been set by Shafaet Ashraf (Shafaet) and Aleksa Plavsic (allllekssssa). Competitors will have 1 hour for solving 4 problems with variable scoring distribution. Contest are rated for all HackerRank users.

I want to thank whole HackerRank team for support and opportunity to organize the new format of competition. Especially I want to thank Shafaet, he is really great guy and his help and contributon in contest preparation are incredible. Also I want to thank wanbo and svanidz1 for testing tasks. I hope that this will become a traditional competition and we'll hang out in one of the following HackerRank contest :)

We are waiting your comments and suggestion about contest :)

Good luck and see you on Thursday !

UPD1: Score distribution : 30-40-60-80

The second and third problems have binary score.

UPD2: Contest starts in 15 minutes. Are you ready to become first HourRank winner ?

UPD3: Contest is finished. Editorial is published. Congratulation to winners :

1.I_love_Tanya_Romanova

2.Kostroma

3.anta

4.Lewin

5.HellKitsune

Thank you for participation. I hope you enjoeyed in problems. I wish to hear more comments about task and contest. I will try to correct something in future if it is wrong. Thank you again and see you on next HourRank contest :)

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9 years ago, # |
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Auto comment: topic has been updated by allllekssssa (previous revision, new revision, compare).

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9 years ago, # |
  Vote: I like it 0 Vote: I do not like it

Auto comment: topic has been updated by allllekssssa (previous revision, new revision, compare).

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9 years ago, # |
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Auto comment: topic has been updated by allllekssssa (previous revision, new revision, compare).

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9 years ago, # |
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What about the level of the problems? For whom, you suppose, will they be interesting?

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    9 years ago, # ^ |
      Vote: I like it +3 Vote: I do not like it

    The tasks won't be very hard. I expect several top scores. At first I wanted a little harder contest, but HackerRank testers think that current tasks are better for the first round.

    I give my best to invent new and interesting tasks :)

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9 years ago, # |
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I am planning to do this contest. This will be my first contest in HackerRank. Very excited :D

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9 years ago, # |
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Sorry for the stupid question but can somebody tell me what "binary score" mean?

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    9 years ago, # ^ |
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    Yes, 'binary score' means that your solution must pass all testcases for non-zero points.

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9 years ago, # |
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Why nothing is written about prizes on Contest page?

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    9 years ago, # ^ |
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    Now everything is ok, you can check Contest page again :)

    Top 10 users will get hackerrank t-shirt.

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9 years ago, # |
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Warmup before #326 :)

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9 years ago, # |
  Vote: I like it +30 Vote: I do not like it

The third problem was quite interesting, thank you!

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    9 years ago, # ^ |
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    How did you solve that one?
    And what is asymthotic of my solution?

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      9 years ago, # ^ |
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      It's not greater than O(n * log^2 MAX)

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    9 years ago, # ^ |
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    Thanks for nice words :) You made this contest better and I hope you enjoyed in solving problems.

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9 years ago, # |
  Vote: I like it +23 Vote: I do not like it

Second problem is awesome :)

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    9 years ago, # ^ |
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    Thank you. I tried to invent interesting and easy problems for implementation. Only I think that I made mistake with the easiest problem — for many logged it was very hard :)

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    9 years ago, # ^ |
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    Yes now after seeing the editorial it seems a very nice solution , i could not think of it during contest.

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9 years ago, # |
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Awesome problems! At least the first 3, I didn't have time to read the 4-th but B and C are really really good, unfortunately I didn't have enough time to code B after I came up with the idea, it' pretty nice! :)

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9 years ago, # |
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Auto comment: topic has been updated by allllekssssa (previous revision, new revision, compare).

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9 years ago, # |
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I got trolled with Problem B. Thought knapsack, gaussian, trie and what not! Then I thought that it's suppose to be "Easy" category, so I should think simple. The category saved me :D

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    9 years ago, # ^ |
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    How did you solved this one?

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      9 years ago, # ^ |
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      Answer is either 0 or 2^(n-1)-1 :D

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        9 years ago, # ^ |
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        Answer is 0 when xor of all the elements of the array is 1 and otherwise, it is 2^(n-1)-1, if I am right. But how does this formula come from, can you give a little insight ?

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          9 years ago, # ^ |
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          Okay, we need to divide an array into two parts with equal xor. We know that A xor A = 0, so XOR of whole array must be 0 as well.

          Okay, now we know that answer is 0 if array's XOR is not zero. Otherwise, let's choose any subset and call it L. And call other half as R. Then L xor R = 0 and R = 0 xor L = L. Finally we've got L = R and that's why we can divide an array in any way. So answer is 2^(n-1)-1.

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9 years ago, # |
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allllekssssa sir ; All problems were very interesting...But,could not notice how fast the contest ended... :/

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9 years ago, # |
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Contest are rated for all HackerRank users Are you sure? Still no rating updates.

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    9 years ago, # ^ |
    ← Rev. 2   Vote: I like it +3 Vote: I do not like it

    Contest is rated, for sure. I don't work for HackerRank, so I can not tell you when rating will be updated.

    The next HourRank round will be organized for 15 days and it will be prepared by svanidz1 ! I am really happy that they are support my idea and we have one new interesting contests in coder calendar :)

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9 years ago, # |
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Thanks for the great contest! HourRank 3 is on Dec 2, 2 am — 3 am GMT/BST. Can't wait to participate in it!

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