Hey everyone,

We're already in August 2025, and many of us are starting to wonder… Where is the Meta Hacker Cup 2025 announcement?

Last year, registration opened on July 24th, and the contest has traditionally started around this time every year.

So far, there has been no official blog post, no website update, no public registration link — nothing.

This silence is worrying, especially in a time when other major contests like Google Code Jam and Kick Start have been officially discontinued. Hacker Cup has always been one of the few remaining global gems of competitive programming, and we really don’t want to lose it too.

Hi Codeforces!

We’re a group of passionate competitive programmers from 1337 School, Morocco, excited to announce our new project that aims to bring competitive programming closer to everyone — even those who’ve never tried solving a problem before!

What’s Our Idea?

In the CP community, we care deeply about content — problem quality, clever ideas, elegant solutions. But outside our world, many people have never even seen these brilliant problems because they’re buried in plain text, code snippets, and contest archives.

So we thought:

→ Why not take some of the classic gems of competitive programming and present them with great design to attract the broader public?

Instead of endless scrolling through social media, people could stumble upon a well-designed post with an intriguing problem that sparks curiosity.

Our Approach

We’re not inventing entirely new problems every time. Instead, we want to highlight classic problems from the CP world — elegant, beautiful problems that deserve a wider audience.

Each week, we’ll share 3 curated problems on our Instagram and X (Twitter) accounts.

We’ll design the posts to be visually engaging, modern, and easy to read, so even non-programmers feel tempted to try solving them.

Why Classic Problems?

They’re time-tested and loved by the CP community.

Many of them are surprisingly approachable for beginners if presented well.

Great design can make them feel fresh and accessible — like discovering a hidden gem.

We believe design matters if we want to reach beyond our usual community and show the world how fun problem-solving can be!

Join Us!

If you’re:

A competitive programmer who loves classic problems,

A designer excited to make CP posts look amazing,

Or just someone curious to try brain teasers instead of scrolling social media…

Follow our pages and join our mission to share competitive programming with the world!

Let’s give classic CP problems the spotlight they deserve.

Account links:

Instagram: @cpc_challenges

X (Twitter): @CPChallenges

— The 1337 CP Club, Morocco

I just found this problem and i don't have any idea how to solve it .

Given an array A of n distinct elements ai such that 1 <= ai <= 10^12 and 1 <= n <= 10^5 Find the length k of any sequence of indices i1,i2,....,ik ( 1 <= i1 < i2 <....< ik <=n )

1. Such that there exists an integer m (m > 1) that satisfies ai1 = ai2 = ... = aik (mod m) .

2. k is maximized

Sample :

Input

5

6 11 16 21 26

Output

5

Given an array of size n <= 10^5 initially filed with zeros, answer two types of queries:

1 A B C : Perform the following operation arr[i] = max(arr[i],C) , where i = A (MOD B) and 1 <= i <= n .

2 I : Print value arr[I] .

Constraints : 1 <= A < B <= N and C <= 10^9

1 <= I <= N .

1 <= n , q <= 10^5 .