# Project Euler | Problem 14 | Longest Collatz Sequence

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__Problem Description__:

The following iterative sequence is defined for the set of positive integers:

`n`→

`n`/2 (

`n`is even)

`n`→ 3

`n`+ 1 (

`n`is odd)

Using the rule above and starting with 13, we generate the following sequence:

13 → 40 → 20 → 10 → 5 → 16 → 8 → 4 → 2 → 1

It can be seen that this sequence (starting at 13 and finishing at 1) contains 10 terms. Although it has not been proved yet (Collatz Problem), it is thought that all starting numbers finish at 1.

Which starting number, under one million, produces the longest chain?

**NOTE:**Once the chain starts the terms are allowed to go above one million.

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__Concept__:

This is very simple problem. If you know the way to find even/odd numbers and maximum number then you can easily solve this problem.

Figure1 |

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__Java Program:__

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__Output:__

Figure2 |

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References:

References:

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Project Euler | Problem 14 | Longest Collatz Sequence
Reviewed by Rohit Agarwal
on
10/14/2017
Rating:

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