Questions tagged [counting]
For challenges regarding counting the number of occurrences of some characteristic.
110
questions
23
votes
2answers
1k views
Eye test - How many squares are in this picture?
The picture:
Sick of the same old grid where the answer is simply a square pyramidal number?
Accept the challenge and write a program that given a positive integer \$n\$ counts how many squares are ...
2
votes
1answer
244 views
Remove duplicates from list and order it by count? (python 3)
How do I remove all duplicates from list and order it based on count?
...
13
votes
6answers
432 views
Number of solutions to a binary weight equation
We define \$a(n)\$ as the 1-indexed position of \$n\$ in the sequence of positive integers with the same binary weight, i.e. the same number of 1's in their binary representation. This is A263017.
...
25
votes
7answers
893 views
Analyze the flow
On a toroidal square grid (you can wrap around) where each cell indicates one direction (^ > ...
32
votes
6answers
2k views
Slash the matrix
You are given a matrix of forward and back slashes, for instance:
//\\
\//\
//\/
A slash cuts along the diagonal of its cell corner-to-corner, splitting it in ...
5
votes
19answers
315 views
How many spaces are there? [duplicate]
Your task is to input a string, and output the number of spaces in the string.
This is code-golf, so least number of bytes win. Your
Test Cases
Double quotes are not part of the test cases.
...
33
votes
28answers
3k views
Count rook moves 1D
Given a position with a row of rooks and/or empty spaces, output how many different rook moves are possible. A rook can move left or right to an empty space, but not to one that requires passing over ...
3
votes
1answer
171 views
Black and white shirt 2
This is a more complicated version of this puzzle. The premise is the same but a few rules differ in a few key places, making for a more complex problem.
Assume I have some number of black shirts and ...
24
votes
43answers
4k views
Character Frequency in a String [duplicate]
Given a string of printable ASCII, output the frequency of each character in that string.
The Challenge
Input is given as a string of printable ASCII characters (decimal ...
26
votes
21answers
5k views
A scene of Jimmy diversity
As you probably know, there have been multiple lovely Jimmy challenges recently popping up. In these challenges, you were challenged with our beloved friend's acrobatics skills. Now we've got a ...
43
votes
23answers
6k views
Covering a Skyline with brush strokes
Given a non-negative integer skyline height list, answer how many uninterrupted 1-unit-high horizontal brush strokes are needed to cover it.
[1,3,2,1,2,1,5,3,3,4,2]...
0
votes
0answers
115 views
Count the score of a Code Golf code [duplicate]
My challenge is to make a Java method(s) that is given a String (another code in Java), removes any unnecessary characters, counts and returns the score, and displays the cleaned-up code in a way that ...
19
votes
32answers
3k views
How fast am I vrooooming?
Introduction
My car speedometer was hacked! Instead of showing me how fast i'm driving, it just shows: "Vroooom!" Please help me know how fast i'm going.
Challenge
Take a string as input, ...
21
votes
5answers
416 views
Count cyclically self-describing lists
Cyclically self-describing lists
A list \$L\$ of positive integers is cyclically self-describing, if the following conditions hold.
\$L\$ is nonempty.
The first and last elements of \$L\$ are ...
7
votes
14answers
3k views
Recursively count lines of code, excluding empty lines and comments
Requirement: Write a program (in any language) that counts the number of lines of code in files matching *.sh in the directory tree starting from the directory that ...
17
votes
18answers
4k views
Longest Repeating Subsequence of a Single Digit
Challenge:
Given a positive integer, output the longest single-digit subsequence that occurs at least twice, AND has boundaries of another digit (or the start/end of the integer).
An example:
Input: <...
10
votes
5answers
611 views
Saddle points in a matrix
A matrix can be thought of as the altitudes of a surface in 3D space.
Consider the 8 neighbours (orthogonal and diagonal) of a cell as a cyclic sequence in clockwise (or anticlockwise) order. Some ...
-13
votes
20answers
405 views
How long is this string?
It's strange this question hasn't been asked yet, so here it is:
Calculate the length of a string given through STDIN
Rules
As said, your string will be given through STDIN, not via command line ...
16
votes
10answers
3k views
Assign Airliner Seats
Inspired by last week's APL lesson.
Given an uppercase 2D seat map and a 1D list of customers, return the seat map and the customer list but modified as follows (to indicate occupied seats and seated ...
33
votes
22answers
3k views
Alphabet Histogram
Given an input sentence consisting of one or more words [a-z]+ and zero or more spaces , output an ASCII-art histogram (bar ...
20
votes
21answers
1k views
Count the Matchsticks
Most people here are familiar with seven segment displays, which are also used in matchstick puzzles. Below are the digits 0 through ...
3
votes
2answers
78 views
Count stacking sequences [duplicate]
Given a list of stack heights, calculate the number of ways those heights could have been arrived at by stacking blocks one at a time. Shortest code wins.
Test cases:
...
23
votes
25answers
1k views
Count edits accounting for grace period
When you edit a post on SE, any further edits within a 5-minute grace period are merged into it. Given a list of times you edit a post, count the edits not in a grace period.
Say you edit at minutes <...
35
votes
24answers
3k views
Plus Primes vs Minus Primes
Most of us know...
that all primes p>3 are of the form
But, how many are the Plus Primes (6n+1) and how many are the ...
16
votes
11answers
804 views
Sequence Without Sevens [duplicate]
This challenge is based on a drinking game. I advise against alcohol consumption while programming.
In this game, the players count up in turns: the first player says ...
24
votes
28answers
2k views
Count forth and back then double up
Let's count...
Count up to 2 and back to 1
Count up to 4 and back to 1
Count up to 6 and back to 1
... ok you got it...
put all these together and you'll get the following sequence
...
26
votes
9answers
1k views
Number Lockers!
Given a positive integer < 100 (from 1 to 99, including 1 and 99), output that many lockers.
A locker is defined as the following:
...
20
votes
19answers
3k views
How much reputation does a steam user have? [closed]
Introduction
For those not familiar with steam - or at least this particular aspect:
Often on peoples' profiles, people leave comments saying either "+rep _____" or "-rep _____". These are an ...
12
votes
11answers
2k views
Count how many months are having a full 31 days by counting knuckles
How many of you that still use your own knuckle to determine whether a month is having a full 31 days or less?
You job is to write a program to count how many months, in a month range, are having a ...
7
votes
1answer
313 views
Count # of Cookie Chocolate Chips
Note: this is my first post here.
The Challenge
The challenge is to count the number of chocolate chips in a cookie. A cookie in this case is a circle with dots (the chips) in it. Given any square ...
33
votes
60answers
4k views
GET your dubs together
On 4chan, a popular game is get. Every post on the site gets a sequential post ID. Since you can't influence or determine them, people try to guess (at least a part of) their own post number, usually ...
18
votes
8answers
3k views
How Many Holes?
Challenge
Given a graphical input of a shape, determine how many holes there are in it.
Not Duplicate
This question was marked as a possible duplicate of Count Islands. I believe this challenge is ...
24
votes
5answers
655 views
How great is your land?
In this challenge, you'll calculate how great your land is.
Write a program or function that calculates the size of your land, given a wall you have built. You're given a non-empty input string ...
10
votes
18answers
1k views
Round the string
Some decimal numbers cannot be precisely represented as binary floats due to the internal representation of the binary floats. For example: rounding 14.225 to two decimal digits does not result in 14....
35
votes
53answers
5k views
How much do I have to write?
Writing out numbers is among the Hello worlds of programming, often the numbers 1-10.
I want to write out many numbers! Many, Many numbers. But how many numbers do I have to write?
Task
Given an ...
6
votes
14answers
596 views
Find the frequency of triplets in a phrase
For context, this problem is based on a old chat-bot project I did.
Problem:
Given a string of words containing any of the characters:
...
58
votes
25answers
5k views
Cantor's unspeakable numbers
An unspeakable number is a number which is divisible by seven or has seven as one of its digits. A children game is to count skipping unspeakable numbers
...
20
votes
20answers
1k views
Find the “Recursive Size” of a List
Inspired by Find the “unwrapped size” of a list.
Define the Recursive Size, RS, of a list containing no lists as its length (number of items contained) and the ...
12
votes
33answers
2k views
Find the “unwrapped size” of a list
Let's define the "unwrapped size" function u of a nested list l (containing only lists) by the following rules:
If ...
59
votes
54answers
4k views
Count trailing truths
Inspired by, and in memory of, my dear friend and colleague,
Dan Baronet, 1956 – 2016. R.I.P.
He found the shortest possible APL solution to this task:
Task
Given a Boolean list, count the number of ...
46
votes
23answers
9k views
Count down from “Infinity”
Seems like an impossible task right? Well, it's actually not that hard. If we write the word Infinity as 8-bit binary ASCII code, we'll get:
...
21
votes
20answers
6k views
A penny saved is a penny
...counted!
You will pass your program a variable which represents a quantity of money in dollars and/or cents and an array of coin values. Your challenge is to output the number of possible ...
-4
votes
3answers
107 views
Get dimension of a list [duplicate]
Find out the dimension of a simple nested list:
[] -> 1
[[]] -> 2
[[[]]] -> 3
...
List taken as input, dimension as output.
No counting length of ...
35
votes
24answers
7k views
Checkmate (aka the urinal problem)
My Precalc teacher has one of his favorite problems that he made up (or more likely stole inspired by xkcd) that involves a row of n urinals. "Checkmate" is a ...
37
votes
15answers
5k views
How long is a Welsh word?
Write a program or function which receives as input a string representing a Welsh word (UTF-8 unless otherwise specified by you).
The following are all single letters in Welsh:
a, b, c, ch, d, dd, ...
41
votes
18answers
6k views
Count to 100 in Danish
Print all the numbers from 0-100 in the right order using the Danish way of counting
How they count
Like English, they have dedicated words for 0-20, 30, 40 and 100
Instead of saying ...
11
votes
7answers
388 views
Create an unlimited counterstring
A counterstring is some sort of self-describing test data that is used in software testing. Not sure it was actually invented by James Bach, but I know it from there.
The idea is as follows: the test ...
39
votes
24answers
4k views
How many lights are on?
You are little speck on a Cartesian plane. Pondering your existence, you decide to roam around your plane and touch things. You notice that every coordinate pair you visit has a light switch. To ...
8
votes
1answer
295 views
Count blocks in a 2D grid
Challenge description
Let's define an W x H grid as a two-dimensional array of length H ...
24
votes
16answers
2k views
Prime Wednesdays
Prime Wednesdays
Your task is to count the number of Wednesdays that fall on a prime day of the month in a particular year. For instance, 7-13-16 is a prime ...
