task stringlengths 0 154k | __index_level_0__ int64 0 39.2k |
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Identifying Map Tiles
Description:
Map websites such as Bing Maps and Google Maps often store
their maps as many different image files, called tiles. The
lowest zoom level (level $0$) consists of a single tile with a
low-detail image of the whole map, zoom level $1$ consists of four tiles each
containi... | 28,200 |
Ignore the Garbage
Description:
Fred works as an IT consultant in an insurance company. As
they always had a large amount of customers waiting and arguing
at the front desk, management decided to deploy a ticket
machine. Each customer would get a ticket with a number and
there will be fancy LCD display... | 28,201 |
Igra
Description:
Having solved a tedious assignment, Mirko decided to play a
game with his good friend Slavko.
They have written a sequence of $N$ letters on a piece of paper. Each
one of them is trying to put together a word using letters from
the sequence. They alternate taking turns consisting of
... | 28,202 |
Iks
Description:
Mirko’s great grandmother Katica is an avid mathematician.
She likes to torment Mirko with math games. This time she wrote
down a sequence of numbers on a piece of paper and told Mirko
he may do the following:
* Choose any two numbers in the sequence (let’s call them
$A$ and $B$) ... | 28,203 |
Illiteracy
Description:
Illiteracy is a simple puzzle game created by Le
Sio. 1 The game consists of a sequence of
eight icons; the actual icons are very artistic, but for
simplicity, we’ll label the icons using a capital letter
A—F.
Clicking any icon has a unique effect on the other icons, based
... | 28,204 |
Illuminated City
Description:
To make the city more pleasant, the municipality of Lund has
decided to install light strips over the streets. The
municipality prefers to have lighting in as many places as
possible. There are many locations where light strips could be
installed, and since the city counci... | 28,205 |
Illuminati Spotti
Description:
One of Xxayvier’s favorite pastimes is spotting triangles
due to his obsession with the Illuminati. Xxayvier has taken it
to the extreme and has been trying to spot triangles on the
larger scale.
He believes that the Illuminati has control of all cities
which have $3$ un... | 28,206 |
Illumination
Description:
Consider a square grid with lamps in fixed locations. Each
lamp can either illuminate its row or its column, but not both.
The illumination of each lamp extends over a limited
distance.
Any square in the grid should only be illuminated by at most
one lamp in its row and by at... | 28,207 |
Image Compression
Description:
Saskia wants to reduce the bandwidth usage of her website,
and has investigated how she can compress her PNG images. She
got a bit curious on how PNG image optimizers work, and before
she knew it, she started working on her own!
In PNG, an image is considered a grid of $Y$ r... | 28,208 |
Image Decoding
Description:
You have been placed in charge of your company’s archive of
digital data, and your first job is to convert a lot of old
pictures into a newer format. But you have no software to read
the old images, so you need to write it.
You do have a description of the old image format. The... | 28,209 |
Image Processing
Description:
Image editing software like Photoshop provide many image
effects like blur, sharpen, and edge detection. These effects
are commonly implemented through a kernel, a matrix describing
a certain image effect. The kernel is applied to an image
through convolution: flipping bot... | 28,210 |
Immortal Porpoises
Description:
As everyone knows, immortal porpoises live on the other side
of straight lines and eat live seagulls, although Federal Law
prohibits transporting the gulls to them (but that’s another
story).
The well-known scientist Leo $O$. Pisa studied immortal porpoises
at great len... | 28,211 |
Impartial Strings
Description:
Alice builds machines that generates strings. Alice’s
machines each consist of $N$ states, numbered from $1$ to $N$, and a set of directed edges
between these states, each labelled with a character from a
fixed set. A subset of the states are “final” states. The
machine g... | 28,212 |
Imperfect GPS
Description:
Lots of runners use personal Global Positioning System (GPS)
receivers to track how many miles they run. No GPS is perfect,
though: it only records its position periodically rather than
continuously, so it can miss parts of the true running path.
For this problem we’ll consid... | 28,213 |
Imperial Measurement
Description:
The traditional imperial system has eight units of
distance (excluding maritime units and some units used in
surveying), related as follows:
thou (th)
inch (in)
1000 thous
foot (ft)
12 inches
yard (yd)
3 feet
chain (ch)
22 yards
furlong (fur)
10 chains
mile (mi... | 28,214 |
Implementation Irregularities
Description:
Impressed by the performance of the top teams at the recent
BAPC preliminaries, you started to wonder whether teams were
allowed to use one or multiple computers to implement their
solutions.
Instead of unnecessarily bothering the organization with
more quest... | 28,215 |
Import Spaghetti
Description:
As you sit down and think, you decide that the first thing
to do is to eliminate the cycles in the dependency graph. So
you start by finding a shortest dependency cycle.
## Input
The first line of input contains a number $n$, $1
\le n \le 500$, the number of files. Then foll... | 28,216 |
Impossible Prices
Description:
Dio’s parents have recently retired to a villa in Greece,
leaving him in charge of the family business, a home decor
store specializing in ancient pottery (and a proud member of
ICPC, the International Consortium of Pottery Companies). Dio
enjoys interacting with customer... | 28,217 |
Impressive Integers
Description:
Recently, Alice and her sister Clara learned about
adorable numbers: A positive integer $n$ is called adorable if there exist
some integers $a, b,$ and
$c$ so that an equilateral
triangle with side length $c$ can be tiled with $n$ smaller equilateral triangles,
each... | 28,218 |
In Case of an Invasion, Please...
Description:
After Curiosity discovered not just water on Mars, but also
an aggressive, bloodthirsty bunch of aliens, the
Louvain-la-Neuve municipal government decided to take
precautionary measures; they built shelters in order to shelter
everyone in the city in the e... | 28,219 |
In Flagrante Delicto
Description:
“[There] is a reason why the most
successful trial lawyers are often master storytellers, making
their cases come to life for their jurors.” –G. Christopher
Ritter.
A good lawyer can take an incomplete set of facts and turn
it into a convincing story.
Last night, a ... | 28,220 |
InTents
Description:
A circus is constructing their tent. The tent is a large
piece of canvas held up by a given number of various length
tent poles. The tent poles go in specific places on the ground,
but which tent pole goes in which place is up to you. You need
to choose a placement for the given te... | 28,221 |
Incognito
Description:
## Input
On the first line one positive number: the number of test
cases, at most 100. After that per test case:
* one line with an integer $n$ ($0\le n \le 30$): the number of
available attributes.
* $n$ lines with two
space-separated strings: the name and the category of... | 28,222 |
Incomplete Sort
Description:
Merge sort is a sorting algorithm. It works by splitting an
array in half, sorting both halves recursively and then merging
those halves together to sort the entire array. Your friend is
working on an implementation of the merge sort algorithm, but
unfortunately he is not q... | 28,223 |
Increasing Subsequence
Description:
A strictly increasing sequence is a sequence of numbers
$a_1, a_2, \ldots , a_ n$
such that, for $1 < i \le
n$, $a_{i-1} < a_
i$. A subsequence of $a_1,
a_2, \ldots , a_ n$ is identified by a strictly
increasing sequence of indices, $x_1, x_2, \ldots , x_ m$ ... | 28,224 |
Incredible Bartender
Description:
Lars is a bartender in Scrollbar, but he is no regular
bartender.
He knows incredible recipes where he can mix a little bit of
this, and a little bit of that, and suddenly, he magically has
a new drink. This process can even increase or decrease the
total amount of li... | 28,225 |
Incremental Double Free Strings
Description:
A string is called double free if no
two adjacent letters are the same.
A string is called $k$-incremental if for all values
of $j$ in the range
$[1,k]$, there exists
exactly one character with $j$ occurrences, and the string’s
length is $1+2+3+\ldots
... | 28,226 |
Incremental Induction
Description:
According to the ancient customs, contestants who have not
been inducted into the Hall of Fame yet (the pathetic nobodies)
must stay on the left side of the stage, whereas contestants
who have been inducted (the awesome legends) must be on the
right side of the stage.... | 28,227 |
Indistinguishable Sequences
Description:
SoCCat defines a map $L:
\bigcup _{i\in \mathbb N} \mathbb Z^ i \to \mathbb N$
which takes in a sequence $\mathbf s = (s_1, s_2, \ldots , s_
k)$ of integers and outputs the length of a longest
(strictly) increasing subsequence of $\mathbf s$.
Two sequences $\ma... | 28,228 |
Indoorienteering
Description:
Lukáš really likes orienteering, a sport that requires
locating control points in rough terrain. To entertain the
NWERC participants Lukáš wants to organize an orienteering
race. However, it would be too harsh for the participants to be
outdoors in this cold Swedish Novemb... | 28,229 |
Infection Estimation
Description:
While it will take some time until tests get into mass
production, one of the research labs is able to perform up to
$50$ tests per day. To
improve test efficiency, the researchers have decided to
combine tests from multiple people. Each test takes in tissue
sample... | 28,230 |
Infiltration
Description:
Rookie Pirate Captain Jack Albatross has secretly laid
anchor in a hidden bay not far from Port Wine, the local
meeting point for grizzled pirates and denizens of the sea.
Disguising as a messenger, you have infiltrated the service of
the dreaded legendary Captain Stevie, and ... | 28,231 |
Infiltration
Description:
Good morning, agent W-12. Your mission, should you choose to
accept it, is as follows.
We are infiltrating the ever so insidious Association of
Chaos and Mischief (ACM) in order to take down their command
structure. Unfortunately, they appear to be prepared for such
an eventu... | 28,232 |
Infinite 2D Array
Description:
We define an infinite two dimensional array $F$ using the following formula:
* $F_{0, 0} = 0$,
* $F_{0, 1} = F_{1, 0} =
1$,
* For $i \ge 2$,
$F_{i, 0} = F_{i-1, 0} +
F_{i-2, 0}$,
* For $i \ge 2$,
$F_{0, i} = F_{0, i-1} +
F_{0, i-2}$,
* For $i,... | 28,233 |
Infinite Cash
Description:
Svalur Handsome has finally graduated with a degree in
computer science, and it couldn’t have happened sooner. He has
some rather unwise spending habits which he hopes will be more
sustainable now that he can get a high paying job as a
programmer. He has applied to a few plac... | 28,234 |
Infinite Race
Description:
Every year, there is a marathon in Eindhoven. This year, the
organizers have come up with something special, and instead of
being over after 42 kilometres, the race goes on forever! To
keep the organization simple, the race takes place on a running
track at Eindhoven universi... | 28,235 |
Infinite Slides
Description:
Agneta and Beata are visiting the famous Swedish Amusement
Park of Infinite Fun and Games. Their favourite attraction is
the Infinitely Long Slides. Each slide can be viewed as an
infinitely long, completely vertical spiral of radius
$1$.
When projected into the (flat) gro... | 28,236 |
Infinitely Long Game
Description:
Alice and Bob will play in a directed
graph $H$. The
$i$-th vertex in
$H$ initially has a value
$Y_ i$. The game will
proceed as follows.
If $H$ contains a
cycle, then the game is a tie.
Otherwise, Alice and Bob will take turns to choose a vertex
in $H$ t... | 28,237 |
Inflation
Description:
To avoid inflating the balloons by hand, the organisers also
bought $n$ helium gas
canisters. Each canister can only be used to inflate one
balloon, and must be emptied completely into that balloon (it
is not possible to disconnect a canister from a balloon before
the caniste... | 28,238 |
Inflation
Description:
People in southern Sweden are known to eat falafel a lot.
The price of falafel is highly volatile, and the best way to
analyze the state of the economy is to go to the same falafel
place every day and add up all the prices on their menu.
A falafel place has $N$
different dishes ... | 28,239 |
Influencers
Description:
You are a manager at an ad agency looking to hire the best
new influencers to promote your clients’ products. Since you
want to build an effective team, you’re looking for influencers
who have positive effects on other influencers when they appear
together.
Meanwhile, $n$
... | 28,240 |
Ingredients
Description:
The chef of a restaurant aspiring for a Michelin star wants
to display a selection of her signature dishes for inspectors.
For this, she has allocated a maximum budget $B$ for the cumulative cost, and she
wants to maximize the cumulative prestige of the dishes that
she is showi... | 28,241 |
Inheritance
Description:
The King of Life, the Universe and Everything is nearing the
end of his reign. He has started planning for his eventual
demise by getting a bunch of kids, hoping one of them will take
over after him.
The king has a huge fortune of $P$ suns (the currency of the
Universe). He wa... | 28,242 |
Initials
Description:
When marking computer science assignments, markers like to
mark each student in order of how they are listed in class. The
way the class is listed is quite strange though, a class is
sorted by concatenating the first name to the last name (for
example Harry Potter becomes PotterHa... | 28,243 |
Ink Blots
Description:
Figure 1: 1 White Region
Figure 2: 3 White Regions
Figure 3: 4 White Regions
Drops of dark ink can fall on a white piece of paper
creating a number of round ink blots. Three examples are shown
above. The blots can create multiple distinct white regions. In
the first figure, ... | 28,244 |
Inkay Game
Description:
$456$ Pokémon in
crippling debt are recruited to play the dangerous “Inkay
Game.” In one round of the game, there are $N$ Pokémon contestants numbered from
$1$ to $N$ trying to cross a bridge of glass
platforms of $L$ pairs of
side-by-side glass steps. In each pair, one step... | 28,245 |
Innvolsarinnihaldslýsing
Description:
Ingfríður has grown curious about her internal content
description. She heard that various properties of an individual
can be deduced from these data, so she has to try it. After
getting the data sent over from the company Encode she has
everything she needs. To an... | 28,246 |
Input Scandal
Description:
Inputte is solving their first problems Kattis. Most of the problems
Inputte have solved so far has been relatively easy, since the
number of input rows is always clearly stated in the
problem.
One day, Inputte was trying a whole new problem. The problem
had an unknown amoun... | 28,247 |
Inquiry I
Description:
The Bureau for Artificial Problems in Competitions wants you
to solve the following problem: Given $n$ positive integers $a_1, \dots , a_ n$, what is the
maximal value of
## Input
* A single line containing an integer $2\leq n\leq 10^6$.
* Then follow $n$
lines, the $i$th of
... | 28,248 |
Inquiry II
Description:
For an undirected, simple graph $G = (V, E)$ we call a subset
$V’ \subseteq V$ an
independent set if no two elements of $V’$ are connected by an edge. An
independent set of $G$ is
called a maximum independent set if there is no
independent set in $G$
with strictly more v... | 28,249 |
Insider's Identity
Description:
In a planet far far away, an intelligence agency plans to
send some spies to the Earth to investigate the life there. In
order to ensure the secret and secure of this scouting
campaign, the agency gives a secret ID to each member.
Each ID is a binary string of length $n$. T... | 28,250 |
Inspecting Illumination
Description:
This is an interactive problem
The Zoldyck mansion is enormous, with dozens of rooms and
hundreds of illuminating sources — light bulbs,
chandeliers, lamps, etc.
You are recently hired by the Zoldyck family as a butler.
Your daily job involves sitting in the illuminat... | 28,251 |
Inspiration Manifestation
Description:
Rarity is designing new clothes, and she is looking for some
inspiration! Recently, she learned about the importance of
symmetry, and is trying to find ways to
incorporate this idea into her designs.
To learn more about symmetry, she decided to search for
inspira... | 28,252 |
Installing Apps
Description:
Each app that Sandra installs has a download size
$d$ and a storage size
$s$. To download the app,
Sandra’s phone must have at least $d$ megabytes of free disk space.
After the app has been installed, it then uses $s$ megabytes of disk space on the
phone. The download s... | 28,253 |
Institute of Advanced Category Manipulation
Description:
A certain magazine annually ranks universities across the
country in various categories, as a service for readers who may
be deciding which university to attend. Each university is
given three scores $R$,
$T$, and $S$ (integers from $0$ to $100$)... | 28,254 |
Intact Intervals
Description:
Gustav is an astronaut on the Nordic Celestial Planetary
Craft (NCPC), a large space station in orbit around Mars.
Today, one of Gustav’s tasks is to look over the satefy
routines on board.
The space station consists of $n$ modules arranged in a circle, so
that module $i$... | 28,255 |
Integer Division
Description:
In C++ division with positive
integers always rounds down. Because of this, sometimes when
two integers are divided by the same divisor they become equal
even though they were originally not equal. For example in
C++, $\verb|5/4|$ and $\verb|7/4|$ are both equal to
1, ... | 28,256 |
Integer Estate Agent
Description:
After recent riots in Flatland, the leader has granted
permission to purchase real estate at the famous Zero street to
everyone. Now, not only the noble polygons are allowed to live
there, but pentagons, squares, and even triangles as well (if
they can afford a house a... | 28,257 |
Integer Lists
Description:
The programming language Better And Portable Code
(BAPC) is a language for working with lists of integers. The
language has two built-in functions: ‘R’
(reverse) and ‘D’ (drop).
The function ‘R’ reverses its input list, and
’D’ drops the first element of its input and return... | 28,258 |
Integer Rotation
Description:
An integer $m$ is a
rotated number of some integer $n$ if $m$ can be obtained by moving some
digits from the back of $n$ to the front without changing
their order. In this case, $(n,m)$ is considered as a rotated
pair. For example, $(1234,4123)$ is a rotated pair since
... | 28,259 |
Intellectual Property
Description:
TDP Inc. has decided to sue JCN Inc. for copyright
infringement. To this end, TDP wishes to find infringing
segments within JCN’s code base, to show to selected media
representatives. Since TDP has fired all its technical staff,
it is looking to hire a consultant to b... | 28,260 |
Intelligence Exchange
Description:
Even though they are still high school students, Carmen and
Juni are already top-tier spies.
Carmen and Juni live in Byteland, which can be modeled as an
undirected connected graph with $n$ vertices and $m$ edges. Today morning at exactly
08:00 am, Carmen goes from her h... | 28,261 |
Intelligence Infection
Description:
You are a spy for the Benevolent Agent Protection Center
(BAPC) and have recently obtained some top secret information.
As you are very excited about this discovery, you want to
inform your fellow spies of these newfound documents by sending
a message to each of them... | 28,262 |
Interactive Tic-Tac-Toe
Description:
Mårten is extremely good at tic-tac-toe. He’s so good you’ve
never managed to beat him. Write a program that plays
tic-tac-toe for you, and you might have a chance.
If you don’t know the rules of the game, you can read them
on
Wikipedia.
## Interactivity
This pro... | 28,263 |
Intercept
Description:
Fatima commutes from KTH to home by subway every day. Today
Robert decided to surprise Fatima by baking cookies and
bringing them to an intermediate station. Fatima does not
always take the same route home, because she loves to admire
the artwork inside different stations in Stoc... | 28,264 |
Interception
Description:
The system in question consists of listening devices placed
on the tin-can phone lines of the street (the idea being that
sooner or later the dog doo malefactors will mess up and
discuss their dirty deeds over the phone). Each listening
device is placed on one of the phone lin... | 28,265 |
Interconnectivity Measure
Description:
There is a city consisting of $n$ junctions and $m$ roads. Each road is numbered from
$1$ to $m$. Road $i$ connects junctions $u_ i$ and $v_ i$ bidirectionally. You can travel
between any pair of junctions by traveling through the
roads.
To travel through roads in th... | 28,266 |
Interesting Integers
Description:
Undoubtedly you know of the Fibonacci numbers. Starting with
$F_1 = 1$ and $F_2 = 1$, every next number is the
sum of the two previous ones. This results in the sequence
$1,1,2,3,5,8,13,\ldots
$.
Now let us consider more generally sequences that obey the
same recu... | 28,267 |
Interference
Description:
Physics can be so much fun! Yesterday, your teacher
explained how interference works: If you have two waves, their
heights add up over the whole waves’ length! So if both waves
have a peak, the resulting peak will be even higher. Likewise,
if both waves have a wave trough belo... | 28,268 |
Intergalactic Bidding
Description:
Due to the extremely competitive nature of the auction, as
well as the odd mechanics of the intergalactic currency used
(far too advanced for mere mortals to understand), the auction
was conducted with the following rules:
* only one participant was allowed to make a bid... | 28,269 |
Intergalactic Mortgage
Description:
Many people on Earth want to solve their housing. When they
have not enough money to buy their house or flat, they get
mortgage from some bank and then they pay fixed monthly
payments until they redeem the mortgage.
You may think that paying mortgage for $30$ years is a... | 28,270 |
Intergalactic Team
Description:
The Intergalactic Competitive Programming Contest (ICPC) is
coming up, and it’s time to choose a team that will represent
our planet in this esteemed competition. The ICPC president has
announced the team size for this year’s competition to all
planets that want to compe... | 28,271 |
International Dates
Description:
You read a lot of documents that come from the United
States, Europe, and other countries around the world. The issue
is that their date formats aren’t consistent! The US formats
their dates as MM/DD/YYYY while in Europe they format it as
DD/MM/YYYY. That is, in the US ... | 28,272 |
Interplanetary Tunnels
Description:
One year ago astronauts Alice and Bob set off to explore the
galaxy each going their own way. The time has finally come for
them to reunite and share their findings. Luckily they have set
up a series of “hyper tunnels” between the planets they’ve
visited. Each hyper ... | 28,273 |
Interpreter
Description:
A certain computer has $10$ registers and $1000$ words of RAM. Each register or
RAM location holds a $3$-digit integer between $0$ and $999$. Instructions are encoded as
$3$-digit integers and
stored in RAM. The encodings are as follows:
* $1xy$ means halt
(regardless of t... | 28,274 |
Intersecting Rectangles
Description:
You are given a set of $n$ axis-aligned rectangles in a 2D
plane. For this problem, two rectangles are considered to
intersect if their boundaries contain any common points (in
particular, two nesting rectangles don’t count as
intersecting). Determine if some pair o... | 28,275 |
Intertwined
Description:
NCPC (Nordic Cargo Plane Control) are testing a new engine
for their cargo planes. To this end they have bound a strong
and sturdy infinitely thin rope to the centre of their testing
platform, and to the engine. We will place a coordinate system
onto this testing platform such ... | 28,276 |
Interval Cover
Description:
For this problem, you are given two things: a numeric
interval $[A,B]$, and a
list of other numeric intervals which, when combined, should
“cover” (overlap completely with) the interval $[A,B]$. In particular, you should
find a minimal set of the intervals needed for the
... | 28,277 |
Interval Scheduling
Description:
Consider a set of $n$
intervals $I_1,\ldots , I_
n$, each given as an integer tuple $(s_ i, f_ i)$ with $s_ i<f_ i$, such that the
$i$th interval starts at
$s_ i$ and ends at
$f_ i$. We want to
determine the maximum number of nonoverlapping intervals. More
f... | 28,278 |
Interval Scheduling
Description:
Many couples will dine out on Valentine’s day. To serve as
many customers as possible, a particular Western restaurant
adopts the "Staggered Seating" strategy on the night of
Valentine’s day.
The strategy works as follows: The restaurant divides its
opening hours into ... | 28,279 |
Interview Preparation
Description:
With the internship season coming up, Johnny has began to
prepare for the dreaded technical interviews. Johnny has
upcoming interviews with $C$ different companies. The
$i^\textrm {th}$ company
will make Johnny an offer if and only if his technical skill is
at lea... | 28,280 |
Interview Question
Description:
Your task here is to solve the reverse problem: given a
transcript of part of the game (not necessarily starting at 1),
find possible values of $a$ and $b$ that could have been used to
generate it.
Figure 1 shows some sample sequences for various values of
$a$ and $b$.
... | 28,281 |
Interview Queue
Description:
A very popular position has just opened up at Poodle Inc.
Candidates have formed a queue while they wait for their turn
to be interviewed.
Competition is fierce and each candidate knows that they
will not be selected if another candidate is strictly better
than them. Every... | 28,282 |
Introspective Caching
Description:
However, caches have a nasty tendency to fill up, so at some
point, objects must be evicted from the cache to make room for
new objects. Choosing what object to remove from the cache is
not easy and there are several different algorithms to choose
from.
The marvelous... | 28,283 |
Intuitive Elements
Description:
Brandon is learning the periodic table! However, he doesn’t
like some of the elements because the symbol of the element
contains letters which are not present in the name of the
element. He finds this to be unintuitive, especially because in
other contexts, he expects ab... | 28,284 |
Invasion
Description:
Alien invasion began, and scary man-eating aliens are
establishing their bases all over the country. You are only
safe on the places that are sufficiently far away from all
current alien bases. You need to quickly write a program to
help you determine where to move.
## Input
The... | 28,285 |
Inventing Test Data
Description:
Preparing a problem set is a very hard task. There are
always issues with clarity of problem statements, bugs in our
solutions, input or output data, and so on. Sometimes, despite
our best efforts, these issues are only found during the
contest, and this can really spoi... | 28,286 |
Inverse Factorial
Description:
A factorial $n!$ of a
positive integer $n$ is
defined as the product of all positive integers smaller than or
equal to $n$. For
example,
It is straightforward to calculate the factorial of a small
integer, and you have probably done it many times before. In
this ... | 28,287 |
Inverse Totient
Description:
Euler’s totient function $\phi
(n)$ is defined as the number of integers $j$, between $1$ and $n$, such that the greatest common
divisor of $j$ and
$n$ equals $1$.
Given $\phi (n)$,
compute the smallest possible value of $n$.
## Input
The first and only line contains the... | 28,288 |
Inverted Deck
Description:
Is it possible to restore the order of the cards into
non-decreasing order of their rarity by reversing just one
contiguous batch of cards?
## Input
The input consists of:
* One line containing an integer $n$ ($1 \le n \le 10^6$), the number of
cards in your collection.
*... | 28,289 |
Investigating Imposters
Description:
You have stumbled upon a village. In this village, some of
the people are “imposters”, while the rest are not.
Fortunately, you know that the number of possible imposters is
limited!
You would like to determine who is not an imposter in this
village. To do so, you ... | 28,290 |
Invoker (Easy)
Description:
You are an invoker, a master sorcerer that is able to
command sources of magic.
## Magical Training
There are two sources of magic you can control, $\mathbb {R}$eagus and $\mathbb {I}$magus. Each source has a
potency coefficient in front of it. This potency is a real
number at... | 28,291 |
Invoker (Hard)
Description:
You are an Arch-Magus Invoker, one of the strongest
sorcerers that is able to command sources of magic.
The difference between an Arch-Magus Invoker and a regular
Invoker is that an Arch-Magus holds an advanced degree or is
pursuing a post-doc in mathemagical studies at the Ins... | 28,292 |
Iron and Coal
Description:
The board consists of different cells numbered from
$1$ to $n$ which can contain resources. The
rules for moving from one cell to another are rather
complicated: if you can move from cell A to cell B, it does not
always mean that you can also move from B to A. For example, if... | 28,293 |
Ironman
Description:
An ironman triathlon is a race where participants swim for
$3.86$ km, ride a bicycle
for $180.25$ km, and
finally run a marathon, and it is considered one of the
toughest sport events. Viveka has been training for an even
more challenging competition: the $n$-athlon. In an $n$-... | 28,294 |
Irrational Division
Description:
The game works as follows. Your parents place a $p \times q$-rectangle of the
aforementioned mixed chocolate on a table. You are situated on
the west side of the table and your sister on the south side.
The side of length $p$ is
parallel to the north-south line, while t... | 28,295 |
Is It Even?
Description:
You are a leading programmer at $\text {Company}^\text {TM}$, and have
been given the following task. Given a list of $N$ integers $x_1,\ldots , x_ N$, is their product
$x_1\cdot x_2 \cdot \ldots \cdot
x_ N$ even? You plug away at the problem using every
trick in the book, and ... | 28,296 |
Is Y a Vowel?
Description:
The Vowels are a, e, i, o and u, and possibly
y. People disagree on whether y is a vowel or not. Unfortunately for you, you
have been tasked with counting the number of vowels in a word.
You’ll have to count how many vowels there are assuming
y is a vowel, and assuming y is n... | 28,297 |
Is it My Turn?
Description:
You just returned to your Uno game after a
much-needed visit to the restroom. When you left, the player to
your left had the turn, with play going clockwise. You can see
that in your absence only Skip cards were played. Is it
possible that it’s your turn now?
Each Skip card... | 28,298 |
Is-A? Has-A? Who Knowz-A?
Description:
Two familiar concepts in object oriented programming are the
is-a and has-a relationships. Given two classes A and B, we say
that A is-a B if A is a subclass of B; we say A has-a B if one
of the fields of A is of type B. For example, we could imagine
an object-ori... | 28,299 |
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