Combinatorics Problems

Geometry Forever

Fear no more, this is a problem of geometry! When Moyna was little, he had a math teacher named Shu...

Meeting Place

There is an N*N grid where (r,c) denotes a cell number where r means row number, c means column numb...

String in a Grid 2

Prof. Bari loves to play with string. He is also very skilled in drawing. One day he was drawing a g...

Harry Potter and the Vault of Gringotts

“There was a break-in of Gringotts Wizarding Bank on 1 May, 1998, during the height of the Second Wi...

Circle of Death

Abir is a school going boy, who loves math. Also, he loves to play with stones. Recently he invented...

Counting Murgis

Ever since that wicked thief took away some of her murgis (hens, that is), Meena was ever anxious th...

Cook a Dish

Have you ever cooked something? No? Not a problem! Whenever you try to cook something, you need som...

I Hate Combinatorics!

Rick and Morty are being hunted by the galactic government. They ran away to the cell dimension. The...

String Play

Milo has a string S of length L. Tutu picks a random prefix and Mota picks a random suffix of S. No...

Third Dimension

Mr. J wants to learn about combinatorics. He started reading a book on combinatorics and came across...

Obligatory IDPC Problem

There are n people busy with arranging the upcoming Inter Department Programming Contest (IDPC) 2016...

Compute the Combination

Let P = C(N,0) - C(N,1) + C(N,2) - C(N,3) + … + C(N,N); where C(n,r) is “n choose r”. You are given...

Mr. Ant and His Problem

Mr. Ant has 3 boxes and the infinite number of marbles. Now he wants to know the number of ways he c...

Bad Neighbors

In the strange neighborhood of Nocu, a lot of people lives pretty happily, or so they think. Like mo...

Meera and Solo Chocolates

Meera bought candies from the store. She is now going to distribute those among her N friends. She m...

How Many Paths?

You are at the top left corner[position (1,1)] of a **R X C ** grid. Your destination is bottom righ...

Bad Neighbors 2

As some of you already know, Nocu City has a history of having bad neighbors. These bad ones, take a...

Subset of Sequences

You will be given a set of sequences. Each sequence is a list of numbers. Two sequences are K-simil...

Secret Meeting

The world is terrified by Pandas! After a miraculous chemical explosion, they became smarter; and ev...

Counting is Difficult 2

East West University Computer Programming Club (EWUCoPC) is arranging an Intra-University Programmin...

Trivial Summation

The problem statement is so small. Give you four integers r, a, b, d. Find the summation of all numb...

XOR Master

Imam has been participating in online programming contests for years. His goal is to become a “Maste...

K-th DuoPalindrome

Alice likes playing with Palindromes (strings that read the same backward as forward, such as ‘madam...

Easy Peasy Subset Sum

Little Oishee loves to watch TV. But her mother, who is a math teacher, doesn’t like this at all. Sh...

Mina and Raju

Everyone know about Mina & Raju. They are siblings as well as good friend. The friend-circle of ...

Bad Cook

Mr. Meme has recently moved to a foreign country named “Gloryland” for study purpose. There, he has ...

Irregular Is Tough, Regular Is Easy!

Dr. Bari is working on some chemical formation. He believes that chemicals and shapes that are regul...

Hange and Her Gear

Hange has developed a special gear to attack the Cart Titan. The gear is a round, disc-like object. ...

Interplanetary Mission

The National Space Center(NSC) is planning an interplanetary mission in a new galaxy far far away fr...

Joker's GCD Test

Joker has a sequence P of n integers. Each two elements in the sequence are pairwise distinct. He de...

Pleasant Permutations

A sequence of n integers is called a permutation if it contains all integers from 1 to n exactly onc...