Questions tagged [base-conversion]
Conversion of numbers between positional numeral systems. Most common systems are decimal, binary, hexadecimal etc.
188
questions
4
votes
1
answer
193
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 ...
- 179
7
votes
1
answer
258
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 ...
- 9,712
4
votes
5
answers
149
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\$ ...
11
votes
34
answers
2k
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 ...
- 5,527
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...
- 5,825
15
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 (&...
- 7,828
11
votes
16
answers
986
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 ...
- 561
15
votes
21
answers
743
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, ...
- 73.8k
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 ...
- 499
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 ...
- 16k
20
votes
30
answers
2k
views
Convert from variable-width Two's Complement to Integer
Take an input, and convert it from Two's Complement notation (binary where the first bit is negated, but the rest are taken as normal) into an integer (in a somewhat standard output form). Input can ...
- 1,357
25
votes
16
answers
3k
views
Convert to base i - 1
Given \$ i = \sqrt{-1} \$, a base-\$ (i - 1) \$ binary number \$ N \$ with \$ n \$ binary digits from \$ d_{0} \$ to \$ d_{n - 1} \$ satisfies the following equation.
$$ N = d_{n - 1} (i - 1) ^ {n - 1}...
- 2,325
12
votes
22
answers
1k
views
Convert a string of ASCII characters to base-3 equivalents
Task similar to this one. Take a string of ASCII characters and convert it to base-3 equivalents separated by a space.
For example:
Hello, world!
Should be ...
- 1,885
12
votes
14
answers
1k
views
Lowest integer with no common digits between given bases
Challenge
Given a list of bases for positional numeral systems as input, output the lowest positive integer that when represented in those bases they have no common digits. The input list can be ...
- 5,497
3
votes
11
answers
490
views
Concatenate characters' indexes in the alphabet in the given numeral system
Given a word, get the indexes of each letter in the alphabet.
For example: uncopyrightable becomes: ...
- 533
17
votes
11
answers
2k
views
Write a number in overflowed binary
We all know how binary conversion works: the sequence of bits
$$ b_1, b_2, ..., b_{n-1}, b_n $$
encodes the number
$$ b_1 \times 2^{n-1} + b_2 \times 2^{n-2} + ... + b_{n-1} \times 2^1 + b_n \times 2^...
- 23.3k
13
votes
9
answers
1k
views
Bijective meets mixed base
Background
A bijective base \$b\$ numeration, where \$b\$ is a positive integer, is a bijective positional notation that makes use of \$b\$ symbols with associated values of \$1,2,\cdots,b\$.
...
- 73.8k
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\$
...
- 133
13
votes
9
answers
836
views
Convert to a non-adjacent form
Consider a form of binary where digits can be any of \$1\$, \$0\$ and \$-1\$. We'll still call this "binary" because we convert the digits from base two. For example,
$$\begin{align}
[1, 0, -...
- 49.5k
19
votes
3
answers
388
views
A multiple of n in every base!
In November 2019, Alon Ran published a particularly lovely sequence in the OEIS, A329126:
\$a(n)\$ is the lexicographically earliest string of digits which yields a multiple of \$n\$ when read in any ...
- 8,659
11
votes
13
answers
716
views
'Plane' the numbers in any base!
Inspired by this Numberphile video.
What is planing?
In order to 'plane' a sequence of digits, you need to:
Identify the lengths of the 'runs' (adjacently repeated digits) in the sequence. Non-...
- 2,305
32
votes
15
answers
2k
views
Compute the generalised XOR
The goal of this challenge is to generalise the bitwise XOR function to other bases. Given two non-negative integers \$ x \$ and \$ y \$, and another integer \$ b \$ such that \$ b \geq 2 \$, write a ...
- 391
5
votes
12
answers
936
views
Base-ically Guard
Base: part 1
This is part 2, Strongly suggest you go try out the first one if you haven't tried it.
Story
As one of the solvers, You've managed to get to the door of the base heaven. In front of the ...
- 1,807
8
votes
17
answers
1k
views
Base-ically god
Story
The god of base is opening heaven’s gate for mortals to join the base party. You, as one of the believers, want to follow their steps to ascend to heaven.
But not everyone can get in.
The god ...
- 1,807
25
votes
33
answers
2k
views
Count the trailing zeros
Given two positive integers \$n\$ and \$b\$, such that \$n > 2\$ and \$n > b > 1\$, count the trailing zeros when converting \$n\$ to base \$b\$. Your program should be able to handle any ...
- 49.5k
11
votes
3
answers
357
views
Help me count the Omer
During the 49 days between Passover and Pentecost, Jewish liturgy provides four numerical problems that I've here phrased as code golf problems.
Input/Arguments
These four, in any order, and by any ...
- 29.9k
23
votes
27
answers
2k
views
Based Palindromes
A palindromic number, as a refresher, is any number which reads the same forward as backwards. However, what about palindromes in other bases?
Input
Any integer b ...
- 504
15
votes
12
answers
999
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 ...
- 18.6k
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 ...
- 2,970
23
votes
27
answers
2k
views
Perfect radicals
Given a positive integer number \$n\$ output its perfect radical.
Definition
A perfect radical \$r\$ of a positive integer \$n\$ is the lowest integer root of \$n\$ of any index \$i\$:
$$r = \sqrt[i]{...
- 10.7k
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 ...
- 18.6k
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 ...
- 419
18
votes
7
answers
727
views
Combinatorial Decomposition
In the body of this challenge, \$\begin{pmatrix}n\\k\end{pmatrix}\$ is used to represent the number of combinations of \$k\$ elements of \$n\$, also written as \$\frac{n!}{k!(n-k)!}\$ or \$n\mathrm{C}...
- 2,049
12
votes
8
answers
1k
views
Scientific notation in Base-16
Input a scientific notation number (base 10), output scientific notation in base 16 (as defined below).
Details
In scientific notation, all non-zero numbers are written in the form
$$ m \times 10^n $$
...
- 34k
17
votes
11
answers
2k
views
The Double-Castle Numbers™
Introduction
A double-castle number™ is a positive integer number that has a pattern of $$\underbrace{a\cdots a}_{m\text{ }a\text{s}}b\underbrace{a\cdots a}_{m\text{ }a\text{s}}b\underbrace{a\...
- 6,178
10
votes
2
answers
436
views
Inverse of Conway base 13 function in \$\mathbb{Q}\$
(The \$\mathbb{Q}\$ in the title means rational numbers.)
Background
Conway base 13 function is an example of a strongly Darboux function, a function that takes every real number on any open ...
- 73.8k
13
votes
9
answers
438
views
Minimal Rotate-Right-Double numbers in base n
Task
For a given base \$n \ge 3\$, find the smallest positive integer \$m\$, when written in base \$n\$ and rotated right once, equals \$2m\$. The base-\$n\$ representation of \$m\$ cannot have ...
- 73.8k
19
votes
22
answers
4k
views
Convert to and from Base 94
The challenge
Make 2 programs which convert decimal to and from base 94, or a bidirectional program.
Base 94?
Base 94 is like any other base, but instead of 0 to 9 and letters, it uses ASCII ...
- 2,693
9
votes
12
answers
389
views
Does base n have any Rotate-Left-Double numbers?
Task
A Rotate-Left-Double number in base \$n\$ is a number \$m\$, when its base-\$n\$ digits are rotated left once, equals \$2m\$. The base-\$n\$ representation of \$m\$ cannot have leading zeros.
...
- 73.8k
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 ...
- 1,619
16
votes
16
answers
1k
views
Find the length of a number's "base-jumping" path
Consider a positive integer N written in base b. A sequence is generated from this number by finding the largest digit ...
- 7,349
31
votes
4
answers
4k
views
How close are we, really?
Please note: this is a restricted-source challenge — see details below!
Each natural number \$n\$ has 10 faces: its decimal representations in bases \$1\$ through to \$10\$. For example, the 10 faces ...
- 49.5k
-1
votes
2
answers
284
views
Mirror, Mirror, on the wall. Who's the fairest of them all?
Well, you know it's Snow White, and the evil Queen is at it again. Will Snow White be saved? Will she fall asleep once again? Will the Prince find her?
Challenge:
Given an arbitrary number (>= 2) ...
- 281
44
votes
30
answers
9k
views
French license plates
Sandbox
French License Plates
French license plates come in a sequential order, following a specific pattern of numbers and letters : AB-012-CD
Challenge
Write ...
- 1,043
18
votes
19
answers
2k
views
Simplification of numbers
How, you can’t remember the 6 or 7-digit phone number that appeared on the TV screen for a second?! Using the special technique described below, you will turn into a walking phonebook!
Obviously, the ...
- 607
-1
votes
11
answers
538
views
Convert alphanumeric (base-36) sentences into hexadecimal (base-16) sentences
I use "sentence" here loosely to mean "any sequence of words separated by spaces" and "words" to mean "sequences of alphanumeric (hexatrigesimal) characters unseparated by spaces".
Conversion is from ...
- 642
-2
votes
11
answers
379
views
Convert a number into "bracket" numerals
"Bracket" numerals are a type of 'numerals' I made up once, and thought would be a nice challenge here. Basically, you convert the input number into base 6, and then transliterate the ...
- 119
-2
votes
15
answers
616
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 ...
- 119
1
vote
1
answer
242
views
Pumping quine radix
Inspired (you don't need to know them for this challenge) by the Pumping Lemma for various languages, I propose the following challenge:
choose some basis \$B \geq 2\$ and an integer \$n \geq 0\$
...
- 16.7k
23
votes
29
answers
2k
views
Digital Sumorial
Given an input n, write a program or function that outputs/returns the sum of the digital sums of n for all the bases 1 to ...
- 7,842