# 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...

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...

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 &amp; Raju. They are siblings as well as good friend. The friend-circle of ...

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...