Hello Codeforces community!

I am glad to announce that HackerRank 101 Hack 44 will be held on 13th Dec 2016 at 16:30 UTC. You can sign up for the contest here. Though what's priceless is solving interesting problems and the thrill of competition, prizes make the competition fierce. Top 10 performers will get a HackerRank T-shirt.

The contest will consist of 5 problems with variable scoring distribution. We have tried our best to prepare a nice problem set. Hopefully everyone will enjoy. Also, you'll be able to enjoy the detailed editorials written by the setter.

Good luck and have fun!

Hello Codeforces community!

I am glad to announce that HackerRank 101 Hack 42 will be held on 18th Oct 2016 at 16:30 UTC. You can sign up for the contest here. Though what's priceless is solving interesting problems and the thrill of competition, prizes make the competition fierce. Top 10 performers will get a HackerRank T-shirt.

The contest will consist of 5 problems with variable scoring distribution. We have tried our best to prepare a nice problem set. Hopefully everyone will enjoy. Also, you'll be able to enjoy the detailed editorials written by the setter.

Good luck and have fun!

Hello Codeforces community!

I am glad to announce that HackerRank Weekly 24th edition will be held on 10th Oct 2016 at 07:00 UTC. You can sign up for the contest here.

Though what's priceless is solving interesting problems and the thrill of competition, prizes make the competition fierce. Top 10 performers will get a HackerRank T-shirt.

The contest will consist of 5 problems with variable scoring distribution. We have tried our best to prepare a nice problem set. Hopefully everyone will enjoy. Also, you'll be able to enjoy the detailed editorials written by the setter.

Each day you get to solve a challenge whose difficulty level increases as the week progresses. Challenge score will decrease by 10% every 24 hours.

Good luck and have fun!

Hello Codeforces community!

I am glad to announce that HackerRank 101 Hack 35th edition will be held on 19th March 2016 at 16:30 UTC. You can sign up for the contest here. Though what's priceless is solving interesting problems and the thrill of competition, prizes make the competition fierce. Top 10 performers will get a HackerRank T-shirt.

The contest will consist of 5 problems with variable scoring distribution. We have tried our best to prepare a nice problem set. Hopefully everyone will enjoy. Also, you'll be able to enjoy the detailed editorials written by the setter.

Good luck and have fun!

Hello Codeforces community!

I am glad to announce that HackerRank 101 Hack 33rd edition will be held on 20th Jan 2016 at 16:30 UTC. You can sign up for the contest here. Though what's priceless is solving interesting problems and the thrill of competition, prizes make the competition fierce. Top 10 performers will get a HackerRank T-shirt.

Problems have been set by Sundar and tested by wanbo. The contest will consist of 5 problems with variable scoring distribution. We have tried our best to prepare a nice problem set. Hopefully everyone will enjoy. Also, you'll be able to enjoy the detailed editorials written by the setter.

Good luck and have fun!

Hello Codeforces community!

I am glad to announce that HackerRank Weekly 18th edition will be held on 22th Nov 2015 at 16:00 UTC. You can sign up for the contest here.

Though what's priceless is solving interesting problems and the thrill of competition, prizes make the competition fierce. Top 10 performers will get a HackerRank T-shirt.

Problems have been set by shef_2318 and tested by CherryTree and wanbo. The contest will consist of 5 problems with variable scoring distribution. We have tried our best to prepare a nice problem set. Hopefully everyone will enjoy. Also, you'll be able to enjoy the detailed editorials written by the setter.

Each day you get to solve a challenge whose difficulty level increases as the week progresses. Challenge score will decrease by 10% every 24 hours. To solve the final challenge, you're given an entire weekend.

Tie-breaking rule: For each challenge, we calculate your solved time, t. [t = submit — open] where submit is the time you submitted the solution, and open is the time you opened the challenge. This way, you do not have to worry about solving the challenge as soon as it becomes available.

Good luck and have fun!

Hello Codeforces community!

I am glad to announce that HackerRank 101 Hack 31st edition will be held on 19th Nov 2015 at 16:30 UTC. You can sign up for the contest here. Though what's priceless is solving interesting problems and the thrill of competition, prizes make the competition fierce. Top 10 performers will get a HackerRank T-shirt.

Problems have been set by shangjingbo and tested by wanbo. The contest will consist of 5 problems with variable scoring distribution. We have tried our best to prepare a nice problem set. Hopefully everyone will enjoy. Also, you'll be able to enjoy the detailed editorials written by the setter.

If anyone are interested in sharing their knowledge, you can comment in this post or send message to me directly. We eagerly need bunch of good problems.

Good luck and have fun!

update 1: The editorial has been added, please upsolving the harder problems which you haven't solved in the contest.

update 2: The contest has been unrated because of the bad/misleading statement for the 3rd problem. We are apologize for that. We will show you more high quality contests in the future.

Hello Codeforces community!

I am glad to announce that HackerRank 101 Hack 27th edition will be held on 23th July 2015 at 17:00 UTC. You can sign up for the contest here. Though what's priceless is solving interesting problems and the thrill of competition, prizes make the competition fierce. Top 10 performers will get a HackerRank T-shirt.

Problems have been set by Devendra Agarwal and tested by wanbo. The contest will consist of 5 problems with variable scoring distribution. We have tried our best to prepare a nice problem set. Hopefully everyone will enjoy. Also, you'll be able to enjoy the detailed editorials written by the setter.

If anyone are interested in sharing their knowledge, you can comment in this post or send message to me directly. We eagerly need bunch of good problems.

Because the contest is intersected with the challenge phrase of SRM 663, we decide to postpone our contest for 0.5 hour.

Thank you HellKitsune for pointing this out. I have changed the contest time. You guys can have a good rest after SRM.

Good luck and have fun!

Hello Codeforces community!

I am glad to announce that HackerRank’ SegFault Contest will be held on 28th June 2015 at 12:00 AM CST. You can sign up for the contest here.

Unlike our usual coding contests, this time you have to review code and find bugs faster than others! Allowed languages are C, C++, Java and Python. Though what's priceless is solving interesting problems and the thrill of competition, prizes make the competition fierce. Top 10 performers will get a HackerRank T-shirt.

Good luck and have fun!

grepCode
Contest Time: from June 10th to June 12th.
Contest page

Hello Coders,

Excited to share that Accel Hack is here! The coding contest commences on 06th June 2015 at 10:30 UTC, and will run for 4 hours. You can sign-up for the Accel Contest here.

Please note that contest is open to all for participation, but only contestants from India are eligible for following prizes:

• Exciting career opportunities with fast-growing Indian start-ups from Accel Partners' portfolio.
• Great prizes — MacBook Pro, iPhones, iPads.
• Chance to pitch your business ideas to Accel Partners.

GL&HF,
Wan Bo

Hello Coders,

The 25^th edition of 101 Hack is here. This time we have 5 interesting challenges lined up for you.
The contest commences on 20th May 2015 at 16:30 UTC, and will run for 2 hours. You can sign up for the contest here.

You will get a Hackerrank T-shirt if you ranked in top 10.

The problem statements will be available in English and Chinese.

Problem Setters

PraveenDhinwa

Problem Testers

wanbo

GL&HF

I found this code can not finish in time, anyone knows why it can't finished in 10 iterations? Is it because of something happened to -O2? I do not think the overflow of n will affect the loop if the compiler haven't done some weird work. Sometimes, we need overflow, for example, in rolling hash of string, but why it works properly there and not bellow?

Please help!!!

#include <bits/stdc++.h>
using namespace std;
int main() {
    int cnt = 0;
    for(int n = (1U << 31) - 10; cnt < 10; n++) {
        cout << n << endl;
        cnt++;
    }
    return 0;
}

I always using c++ style cin, cout for solving problems, and hasn't got efficiency issues before. But the following problem has so much difference, please help me why this happens.

Same code with just different input method. http://codeforces.net/contest/396/submission/10835959 => scanf 343ms http://codeforces.net/contest/396/submission/10835934 => cin + sync_with_stdio(0) 1044ms

It seems scanf is much much faster than the cin method even when cin close the sync, this never happened before. I close the sync in the pre-written code: struct _ {_() {ios_base::sync_with_stdio(0);}} _;

Delete: Do not DOWNVOTE me if you think this problem is not high quality, it's hard for me to gain rating, so contribution gain will be also exciting.

**** Add: Feel free to DOWNVOTE me, if you think my contribution is high enough. Hope my sum of rating and contribution will be stable. :D

Problem Link Can anyone figure out my code's bug without running my code? :)
Here is my submission: Submission link

Here is my steps for solving this problem:
- sort the array in decrease order
- extract the consecutive subarray that the difference between the two elements is <= 1.
- greedily choose the edges for rectangles in order.

https://www.hackerrank.com/sep13

The Prizes
Top 10 contestants from global leaderboard will win exclusive HackerRank T-shirts.
Challenge winners : Top contestant from every challenge leaderboard will receive a book.
Daily winners : A contestant who scores highest that particular day will win an exclusive HackerRank T-shirt.

(https://www.hackerrank.com/may13/)