Skip to main content

Problem 5 Project euler solution with python

Smallest multiple

2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder.
What is the smallest positive number that is evenly divisible by all of the numbers from 1 to 20?

To be simple the question asked was to find the LCM(Least Common multiple) of numbers from 1 to 20.

If we use Common Factors Grid method to find the value manually on paper, it can easily be found out.

But to write a program to find the LCM of two or more numbers you should be knowing Euclid Algorithm. But Euclid Theorem was designed for only two numbers. Let us assume that we will have to find LCM of 3 numbers n1,n2,n3. As LCM is both assertive and commutative we can write LCM(n1,n2,n3) = LCM(LCM(n1,n2),n3). This is what I have used in the program.

Also if you don't know what Euclid Algorithm is then Please check out Wikihow - Ways to Find the LCM of two numbers.

Program

So the program which I wrote is as follows:
The program is fast and it just took me 5.19752502441e-05 seconds.
I think this program is pretty simple and there is nothing to explain. So I am not explaining anything.
One thing I want to mention is the possibility to use the reduce function. Instead of using for loop on line31, you can use reduce function.
If you want to download the program then you can download it from Github Gist

Output


Summary

Solving this problem on paper was easy. But converting it to a program took some time for me. I think this problem was easy if you knew Euclid Algorithm, which was not so in my case. So I had to understand the concepts behind the algorithm and this problem became easy for me.

I would like to thank the StackOverflow community and Wikihow which helped me framing the program for this problem.
Least common multiples of 3 or more
How to find the Largest Common multiple of two numbers

Finally as all the code is neatly commented I have not explained anything. But if you have any doubt or didn't understand anything, please do comment in the comment box below and I will be glad to help you. 

Please don't hesitate to comment if you want me to add any extra thing or if I have made any typo. 

You can also contact me if you want to.

Thank you. Have a nice day☺️.

Popular posts from this blog

Making a quiz web app with python and flask

Edit : When you are creating a web app with h tml templates, then y ou will have to sa ve the html file in templates folder in the Current Wor ki ng Directory( CWD). If you save the file in the C W D directl y you will get a TemplateNotFound error. Thank you Udhay for pointing it out.   In this post we will create a quiz website using python . I will be using the flask framework . After reading this tutorial you will learn form submission , flask templates , python code in flask templates , shuffling the questions and options with the random module and few others.  Please note that this tutorial is not big as it seems to be. Some of the code has been rewritten to maintain consistency and also font size is somewhat big so that your eyes won't get stressed reading this tutorial. Also the content has not occupied the full width of the page. In this tutorial I am assuming that you are having a very basic understanding of the flask framework . Please refer the documentation

Problem 11 Project Euler Solution with python

Largest product in a grid In the 20×20 grid below, four numbers along a diagonal line have been marked in red. 08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08 49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00 81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65 52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91 22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80 24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50 32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70 67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21 24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72 21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95 78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92 16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57 86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58 19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40 04 52 08 83 97 35 99 16 07

Problem 60 Project Euler Solution with python

Prime pair sets The primes 3, 7, 109, and 673, are quite remarkable. By taking any two primes and concatenating them in any order the result will always be prime. For example, taking 7 and 109, both 7109 and 1097 are prime. The sum of these four primes, 792, represents the lowest sum for a set of four primes with this property. Find the lowest sum for a set of five primes for which any two primes concatenate to produce another prime. This problem is j u st a brute force problem. If you have come here because you don't know the limit upto which you will h ave to gener ate the prime numbers t hen go ahe ad and t r y with 10,000 . When I first start ed solving the problem I chose 1 million(beca use most of the problem s on project E uler have this limit ), but it took very long for the computer to fin d the solution. After searching on the internet then I found many people choosing 10, 000 so I have changed my in put f rom 1 million to 10000 and the output was f ast. He