# Questions tagged [collatz-sequence]

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

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### 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 ...
1 vote
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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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### 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 ...
• 103
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### 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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### 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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### 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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### 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 ...
• 201
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### 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 ...
762 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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### 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: ...
• 41
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### 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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### "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 ...
• 123
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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 ...
791 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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### 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 ...
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### 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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### 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: ...
• 13
1 vote
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### 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 ...
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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 ...
191 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 ...
• 1,012
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### 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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### Generator for the collatz conjecture sequence

I tried to write this code as concisely as possible. Is this the best way to do it? ...
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