Questions tagged [collatz-sequence]

This tag should be used for code related to the sequences described in the Collatz conjecture.

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Python - The Collatz Sequence

Can I get a review of my code for the the Collatz Sequence from Chapter three of Automate the Boring Stuff with Python? The Collatz Sequence Write a function named collatz() that has one ...
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Project Euler Problem #277

I am trying to solve Euler project problem 277 using python 3.8. First, I will show my program and than ask specific questions for enhancements. The problem is a modified version of Collatz sequence. ...
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237 views

Basic Collatz program with input validation in Python

In chapter 3 of Automate the Boring Stuff with Python by Al Sweigart, one exercise asks to write a program which performs the Collatz sequence. I wrote a basic version first, then added and ...
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1answer
108 views

Collatz Conjecture Disprover Unit - Googol Edition

The Wikipedia article about the Collatz Conjecture has these quotes: If the conjecture is false, it can only be because there is some starting number which gives rise to a sequence that does not ...
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3answers
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Generator for the collatz conjecture sequence

I tried to write this code as concisely as possible. Is this the best way to do it? ...
5
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1answer
73 views

Hailstone Sequence in NASM

For practice, I wrote some NASM code that prints out the hailstone sequence of a (unfortunately, hardcoded) number. This is by far the most complex code I've ever written in NASM. I'd like advice on ...
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1answer
135 views

Collatz sequence using Python 3.x

I created this program originally for Project Euler 14. Here's the code: ...
4
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3answers
340 views

Calculating a Collatz Sequence

I've written a small script to calculate Collatz sequences. For background, read here about the Collatz conjecture. Largest number I've tried so far in my implementation is 93571393692802302 (which ...
4
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1answer
449 views

Computational verification of Collatz conjecture using OpenCL

This code review request follows my previous request Computational verification of Collatz conjecture. Unlike the previous program (which was designed for the CPU), this code should run on modern GPUs....
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4answers
213 views

Optimized Longest Collatz Sequence

I'm writing a program to calculate the longest collatz sequence for positive integers below some N. I have optimized it as far as I can - is there anything more I could do to optimize it? Any ...
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2answers
96 views

Computational verification of Collatz conjecture using gmplib

Prerequisites The unsigned long type has a size of 64 bits. The following macros are defined. ...
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1answer
336 views

Computational verification of Collatz conjecture

Prerequisites The typedef name uint128_t designates an unsigned integer type with width exactly 128 bits. The ...
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1answer
217 views

Automate the Boring Stuff - Collatz Exercise

I wrote the following code for the Collatz exercise: The Collatz Sequence Any feedback is appreciated. Write a function named collatz() that has one parameter ...
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1answer
85 views

python : Collatz Sequence

I am a beginner in python. I found this problem in the book Automate the Boring Stuff with Python. How can I improve this program using latest version of python. ...
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4answers
5k views

Python Automate the Boring Stuff Collatz exercise

I'm looking for some feedback on my code for the collatz function exercise in the Python book Automate the Boring Stuff. It works, but doesn't feel very elegant to me. Is there a better way to ...
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3answers
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Finding the longest Collatz Sequence

Inspired by Project Euler 14: Longest Collatz Sequence "Which starting number, under one million, produces the longest Collatz Sequence chain?" I wrote the following Java code: ...
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1answer
186 views

Finding the longest Collatz sequence using Go, concurrently

I am working through this problem on project euler. Basic purpose of the code: ...
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3answers
2k views

Determine Collatz sequence length for given starting values

I am trying to get into the habit of solving programming puzzles in my spare time but am stuck on the first one (which I know can be for a large number of reasons, hence my posting for help). Shown ...
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4answers
957 views

Testing a Collatz Conjecture Conjecture (Python)

I had an intuition that the maximal trajectory lengths for collatz conjecture numbers would be produced by numbers of the form (2**n)-1 so I wrote a program to test ...
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2answers
366 views

Contest Solution: Hailstones

The Problem In the January 1984 issue of Scientific American, an interesting sequence of numbers known as a hailstone series was described. The series is formed by generating the next number ...
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Automate the Boring Stuff with Python - The Collatz sequence project

I am new to programming and started learning with Automate the Boring Stuff with Python. I just completed chapter 3's "Collatz sequence" project. I was wondering what would you do differently and ...
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1answer
178 views

Longest Collatz sequence in Scala

I am trying to find the longest Collatz Sequence: Which starting number, ≤ N, produces the longest chain? If many possible such numbers are there print the maximum one. (1 ≤ N ≤ 5×106) I tried ...
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Collatz fractal in Rust

Among the many fractals, there is Collatz Fractal based on a complex extension of: $$f(x) = \left\{ \begin{array}{ll} \frac{x}{2} \space \text{if even} \\ 3x + 1 \space \text{if odd} \end{array} \...
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Euler Project 14 Longest Collatz Sequence [closed]

I have been working through the euler project and I have created the following code for Problem 14, which asks which starting number, under 1 million, produces the longest Collatz Sequence chain. It ...
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2answers
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Calculating the Collatz conjecture of a number

I've made a Collatz Conjecture sequence calculator and I would like some feedback on what I can do better in regards to the code I've implemented, i.e. bad practices you see, improvements that can be ...
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2answers
160 views

Euler Project 14 (Longest Collatz Sequence)

Project Euler 14 asks: Which starting number, under one million, produces the longest Collatz sequence? I've been trying to optimize this solution to execute in less then 1s. Agenda for first 50 ...
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1answer
139 views

Generating the Collatz sequence in F#

Below is my code for building the collatz sequence so a given number. I'm trying to make the function tail recursive and I believe that this impelemtation is tail recursive but I'm not yet so ...
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3answers
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Hailstone Sequences in Python

For the problem given: Douglas Hofstadter’s Pulitzer-prize-winning book, Gödel, Escher, Bach, poses the following mathematical puzzle. Pick a positive integer \$n\$ as the start. If \$n\$ is ...
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1answer
137 views

Project Euler problem #14 (longest Collatz chain) in Swift

This is my Swift code for finding the starting number, under one million, which produces the longest collatz chain. ...
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4answers
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Collatz Conjecture (c++)

I am new to C++ and this is my first program. The objective of this program is to fully complete the sequence called the Collatz conjecture. It concerns a sequence defined as follows: start with ...
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2answers
896 views

Memoized Collatz sequence

Here is one of my programs that utilized memoization and array to improve performance and memory usage. The performance seems satisfactory but the memory usage is ridiculous and I can't figure out ...
3
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1answer
328 views

Collatz Conjecture Meet of 2 Numbers

I need the most efficient way to calculate when the Collatz Conjecture of two numbers, a and b respectively, are the same. Here ...
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2answers
401 views

Counting terms in Collatz sequences until 1 is reached or a limit is exceeded

My friend and I are into competitive programming and we wrote two very similar programs for a problem. His got accepted with a runtime of 0.6 s while mine didn't get accepted even after 3 s. I was ...
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3answers
585 views

Longest Collatz sequence using dynamic programming in Java

I'm not getting where else should I optimize it. Is there any way to optimize this code any further? Just give me hints. ...
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2answers
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Project Euler #14 - Longest Collatz Sequence in Python

I recently solved Project Euler Problem 14 in Python: The following iterative sequence is defined for the set of positive integers: ...
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2answers
157 views

UVA 100: “The 3n + 1 problem” take 2

This is my second attempt to solve this problem, my first attempt is here: UVA 100: "The 3n + 1 problem" This time I tried to take lessons from the failures and mistakes You pointed out in ...
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2answers
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"Longest Collatz sequence" in C slower than in Python 3

This tight-looped memoization-less C solution to Project Euler's problem 14 seems efficient, but ran much slower than a similarly trivial Python 3 program. For the desired ...
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4answers
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Project Euler problem 14 (longest Collatz sequence) in Swift 3

I was trying to solve Project Euler:Problem 14 using Swift 3, but it takes ages to give me an answer, which is a sign that my code is absolute garbage performance-wise. What could I do to increase the ...
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2answers
625 views

UVA 100: "The 3n + 1 problem"

I’ve solved UVA Problem 100: The 3n + 1 problem . In short, the task was to write a program that calculates a maximum of Collatz sequence lengths for any given range of starting values. My program: <...
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1answer
8k views

hailstone sequence using recursion in python [closed]

Douglas Hofstadter's Pulitzer-prize-winning book, Gödel, Escher, Bach, poses the following mathematical puzzle: Pick a positive integer n as the start. If n is even, divide it by 2. If n is ...
2
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3answers
581 views

Project Euler: Longest Collatz Sequence

The Collatz Sequence is an iterative sequence that is defined for all positive integers as such: n → n/2 (n is even) n → 3n + 1 (n is odd) If 13 were to be entered into this sequence, the result ...
6
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1answer
479 views

Locating the largest Collatz Sequence with memoization

Inspired by this question I wrote a memoized form of the collatz sequence calculator. The idea was to cache the sequence lengths for as many sequences as possible, from 0 to some value. I managed to (...
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1answer
578 views

Python program for testing the Collatz Conjecture

This is a simple program to test if integers will follow an interesting, improvable statement that if disproven, calls for a bravo. But, ignoring the pretentious poetry, this code allows the user to ...
3
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2answers
533 views

Efficient solution to Project Euler 14 (Longest Collatz sequence)

This is an iterative review. I asked for reviews on a Collatz sequence generator here. I tried to address all of the suggestions that were made. I've added a new function ...
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3answers
2k views

3n + 1 programming challenge in Python

I am trying to find a efficient solution for the 3n + 1 problem on uvaonlinejudge. The code I have uses memoization using a dictionary. I am getting a 'Time limit Exceeded' error when I submit the ...
5
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1answer
3k views

Finding maximum Collatz sequence between 1-1000000

I'm trying to find maximum the Collatz sequence between 1 and 1000000. I wrote the following code below. I guess it is correct but it is extremely slow. Can you give me a few hints to make it faster? ...
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1answer
796 views

Python script to calculate the Collatz conjecture

Here is the code. ...
10
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3answers
4k views

3n + 1 problem optimization

The problem can be viewed here, since it's styled. I don't think I should just copy and paste. I implemented recessive function and dynamic programming to solve it. It can successfully passed UVa ...
5
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1answer
316 views

Syracuse conjecture in OCaml

I am wondering how to optimize the following OCaml simple code. ...