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Questions tagged [base-conversion]

Conversion of numbers between positional numeral systems. Most common systems are decimal, binary, hexadecimal etc.

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13 votes
1 answer
286 views

Where are zeros? Self-describing sequence

Background A167519: Lexicographically earliest increasing sequence which lists the positions of the zero digits in the sequence. ...
13 votes
40 answers
3k views

Convert binary to unary

The title says it all; Given a number in the binary (base-2) number system, output the same number expressed in unary (base-1). You should take the binary number as a string (optionally with a ...
20 votes
22 answers
2k views

Sum of Binary Substrings

This challenge is simple, given a decimal number, convert to binary, and calculate the sum of the sub-strings of the binary number, whose length is shorter than the original number. Here is an example:...
37 votes
39 answers
4k views

16-bit binary grid

Given any unsigned 16 bit integer, convert its decimal form (i.e., base-10) number into a 4x4 ASCII grid of its bits, with the most-significant bit (MSB) at the top left, least-significant bit (LSB) ...
23 votes
23 answers
3k views

Simplify binary

Challenge Given a binary number as input through any means, "simplify" the number using a full program or a function. Input [binary] ...
12 votes
21 answers
2k views

Hexadecimal to Binary

Convert a hexadecimal number (of any size) into a binary number. Input A POSITIVE hexadecimal number with a 0x in the beginning. A valid input will always match the ...
42 votes
51 answers
5k views

Numbers that are actually letters

Given a non-negative integer input, write a program that converts the number to hexadecimal and returns a truthy value if the hexadecimal form of the number contains only the characters ...
23 votes
41 answers
4k views

Increment base-36 strings

This is a code golf version of a similar question I asked on stack earlier but thought it'd be an interesting puzzle. Given a string of length 10 which represents a base 36 number, increment it by one ...
22 votes
17 answers
1k views

All your base palindromic belong to us

Generate the sequence number of bases in which n is a palindrome (OEIS A126071). Specifically, the sequence is defined as follows: given a number ...
18 votes
15 answers
1k views

Non-palindromic numbers

A strictly non-palindromic number N is a number that isn't a palindrome in any base (in bases 2 to N-2). These numbers are listed on OEIS For example, the number 19...
4 votes
1 answer
218 views

Convert real numbers between factoradic and positive integer bases

This prompt asked you to convert back and forth to factoradic, but is very limited in scope (only decimal integers from 0 to 10!-1). Your task in this challenge is to reach just a bit further and ...
7 votes
1 answer
292 views

Literate Programming in Base 26

Your task is to convert non-empty strings - between strings using the 26 letters, and programs, which are strings of bytes, where each byte has 256 possible values. You should use the same codepage ...
4 votes
5 answers
152 views

Base consecutive k-frequency counter [closed]

Given a base \$k\$ as well as two indices (also passed in base \$k\$, call them \$s\$ and \$e\$) return a list containing a frequency count of all base-\$k\$ digits occurring between \$s\$ and \$e\$ ...
22 votes
25 answers
1k views

Possible binaries sum

This challenge is inspired by the AoC 2020, Day 14 - Part II, created by Eric Wastl and his team, which asks to output the possible binary values from a bitmask. Let's say we've a bitmask like ...
15 votes
12 answers
1k views

Compute the Redwolf Checksum™ of some data

I will preface this by saying that I made this for fun; I have absolutely no formal knowledge on cryptography or error correction. Do not use this algorithm in anything remotely important. I was kind ...
11 votes
16 answers
997 views

Multibase Numbers

(Similar: Through the bases) Normally, our number system is base ten, with the digits 0123456789. However, we can increase or decrease the base count (so ...
7 votes
18 answers
9k views

Convert RGB integer value into RGB values

For example, in traditional web hexadecimal, a certain base-16 number represents an RGB value. For example, 45A19C equals (69,161,156) in RGB. You'll be converting from that number to RGB value, ...
7 votes
18 answers
2k views

Minimum base to count to a string

The Challenge Input: alphanumeric string. You can assume that the string will only contain the characters [0-9A-Z]. This can come from a parameter, command line, or STDIN. Digits are always before ...
19 votes
34 answers
2k views

Reverse and square

In this challenge you will compute numbers from a curious sequence. Your input is a single decimal nonnegative integer. Reverse the bits in this integer and then square the number to get the required ...
10 votes
35 answers
2k views

How long is the number in this base?

Given a positive integer \$n\$ and another positive integer \$b\$ (\$1 < b < 36\$), return the number of digits/length of \$n\$ in base \$b\$ ...
32 votes
36 answers
6k views

What base is this number in?

Here's a nice easy challenge: Given a string that represents a number in an unknown base, determine the lowest possible base that number might be in. The string will only contain ...
24 votes
37 answers
2k views

Display the exponent from a binary floating point number as a decimal value

Had my software final exams recently, one of the last questions had me thinking for a while after the exam had finished. Background IEEE754 numbers are according to the below layout The exponent is ...
16 votes
10 answers
2k views

Brainf**k to Unary and Back

A language that is very useful in restricted source and other such challenges is Unary, a brainfuck derivative in which programs are written in with only one character. Your job is to write a program ...
7 votes
13 answers
2k views

Tic Tac Toe encoder/decoder

James Bond is about to start a new mission and you are his computer scientist friend. As Tic Tac Toe is becoming more and more popular you decide that nothing would be more underhanded than a Tic Tac ...
30 votes
45 answers
7k views

Convert a 32 bit binary IPv4 address to its quad-dotted notation

Challenge Write a program or function that converts a 32 bit binary number to its quad-dotted decimal notation (often used for representing IPv4) Quad-dotted decimal A quad-dotted decimal is formed ...
19 votes
10 answers
3k views

Numbers that can be negated by reading backwards

Balanced ternary is a modified version of ternary (base 3), using the three digits 1,0 and -1...
35 votes
20 answers
9k views

Balanced Ternary Converter

Credits for the challenge idea go to @AndrewPiliser. His original proposal in the sandbox was abandoned and since he has not been active here for several months, I have taken over the challenge. ...
31 votes
45 answers
3k views

Up go the bits!

Given an integer N perform the following steps: (using 9 as an example). Receive input N. (9) Convert N from base10 to base2. (...
37 votes
49 answers
10k views

What is the reverse (binary) bit number?

So you are given a POSITIVE base 10 (decimal) number. Your job is to reverse the binary digits and return that base 10 number. Examples: ...
46 votes
84 answers
9k views

Binary to decimal converter

Binary to decimal converter As far as I can see, we don't have a simple binary to decimal conversion challenge. Write a program or function that takes a positive binary integer and outputs its ...
16 votes
6 answers
1k views

Cube calendar numbers

Credit: Marco Verch CC BY 2.0 A two-cube calendar, as shown in the picture, uses two cubes with digits painted on the faces to display the date. For dates in the range 1-9, a leading zero is used (&...
26 votes
17 answers
3k views

Convert negadecimal to decimal (and back)

Negadecimal, also known as base -10, is a non-standard positional numeral system. Take the number \$1337_{10}\$. In decimal, this has the value one thousand three hundred thirty seven, and can be ...
14 votes
22 answers
1k views

Determine if an integer is a palindrome in a given radix (base)

Write a program that reads from stdin two integers, each newline terminated, hereafter called "number" and "radix", and: Prints any fixed message you want if the number is a palindrome in that radix (...
15 votes
21 answers
747 views

CGAC2022 Day 16: Playing with bits, Part 2

Part of Code Golf Advent Calendar 2022 event. See the linked meta post for details. As soon as the Elves get bored with the last week's game, Bin comes up with a new game. The rules are similar, ...
21 votes
20 answers
1k views

Find the longest rep digit

Your task is to take a positive number as input, n, and output the length of the longest rep-digit representation of n in any base. For example 7 can be represented as any of the following ...
33 votes
29 answers
4k views

Smallest Zeroless Base

Given a positive integer n, output the smallest base b >= 2 where the representation of n ...
13 votes
25 answers
2k views

Output the length of (the length plus a message) [duplicate]

The task is simple. You're given an arbitrary string message. Return that message prefixed with a number, such that the length of that number plus the message equals the number. In other words, the ...
-3 votes
15 answers
620 views

Find how "smooth" a number is based on binary

I haven't been on PP&CG for a while, so I thought I would post something! Your task is to find how "smooth" a natural number is. Your method is to: 1: Convert the number to binary 2: Find the ...
17 votes
16 answers
1k views

All the Xenodromes

Introduction A xenodrome in base n is an integer where all of its digits in base n are different. Here are some OEIS sequences of xenodromes. For example, in base 16, ...
43 votes
26 answers
6k views

The best base is 10... Let's reach it!

Input: A positive integer n consisting of digits in the range 0-9. Challenge: If d is the highest digit in the integer, assume the base of the number is d+1. E.g. if the integer is 1256 then you ...
32 votes
32 answers
2k views

Decompose binary into alternating subsequences

This was inspired by Problem 13 - Non-Repeating Binary of HP CodeWars' recent competition. Let's take a random decimal number, say 727429805944311 and look at ...
25 votes
21 answers
2k views

Calculate the binary split sum of a word

Take a string, s containing printable ASCII-characters as input, and output its "binary split sum". Need an explanation? How do you get the binary split sum? We'...
14 votes
11 answers
3k views

Base85 Encoding

The Challenge Write a program that can take an input of a single-line string containing any ASCII printable characters, and output the same string encoded in Base85 (using a big-endian convention). ...
20 votes
20 answers
4k views

Lowest-Base Palindrome

Given a number \$n\$, write a program that finds the smallest base \$b ≥ 2\$ such that \$n\$ is a palindrome in base \$b\$. For example, an input of \$28\$ should return the base \$3\$ since \$28_{10} ...
13 votes
22 answers
2k views

Convert a string of ASCII characters to base-3 equivalents

Task similar to this one. Take a string of ASCII characters and convert it to base-3 equivalents separated by a space. For example: Hello, world! Should be ...
19 votes
25 answers
2k views

Carry-less sum given a base b

Given a list of positive integers \$\mathcal I=I_1,I_2,I_3,...,I_n\$ and a base \$b>1\$ return their "carry-less sum", i.e. represent \$\mathcal I\$ in base \$b\$ and sum digit-by-digit ...
20 votes
27 answers
1k views

Decompose a number!

Your task is to decompose a number using the format below. This is similar to base conversion, except that instead of listing the digits in the base, you list the <...
25 votes
18 answers
2k views

A multiplication table for the Cheela

The Cheela (from the book Dragon's Egg by Robert L. Forward) are creatures that live on the surface of a neutron star. Their body is flat and circular with twelve eyes on the perimeter, so they ...
20 votes
14 answers
1k views

Output N in base -10

Challenge: In the programming language of your choice, accept an integer as input in base 10, and output it in the negadecimal notation, which is also known as base -10 Example algorithm: This is ...
24 votes
14 answers
2k views

ASCII Character Jumble

Write a program that takes as its input a string consisting of printable characters (ASCII 20-7E) and an integer n in [2,16] and performs the following modification ...