Posts Tagged with "API"

Project Euler 37: Find the sum of all eleven primes that are both truncatable from left to right and right to left

Saturday, April 23, 2011

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A new type of prime numbers are the focus of Problem 37 of Project Euler. This time the type of prime numbers is truncatable primes. I have never heard of this type of primes before, but the problem description gives a good explanation.Find the sum of the only eleven primes that are both truncatable from left to right and right to left.So we know that we are supposed to find 11 of these. I will present you with two similar approaches. The first one is pure brute force where we search through all primes until we hit the ones with the right property. In the other solution we will only generate numbers which are left truncatable and then check if the are right truncatable. However, both solutions are missing one important thing I think. They are missing a clear upper bound. I haven't been able to establish one through any means, so if you can share some insight to that I would be very happy to hear from you.

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Project Euler 22: What is the total of all the name scores in the file of first names?

Wednesday, January 12, 2011

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Given problem 22 of Project Euler which reads What is the total of all the name scores in the file?The way I want to solve this problem, is to split it into three parts Read the input file and turn the data into a manageable data structure Sort the data Sum up and provide the answerSo this post will be split into three parts with most focus on the second part, as that is where the meat is. I will swap the sections a bit, such that I treat section 1 and 3 first to set up the framework. At last I will shortly treat two different sorting algorithms plus the .NET API way for sorting.

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Project Euler 20: Sum of Digits in 100!

Wednesday, January 5, 2011

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Given problem 20 of Project Euler which reads Find the sum of the digits in the number 100!I exploit the BigInteger class in .NET 4.0 which makes it easy to operate on large integers, and thereby makes it a matter of slicing up the big number.

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Project Euler 19: How many Sundays on the first of a month

Saturday, January 1, 2011

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Problem 19 of Project Euler is a curious little problem. It asks How many Sundays fell on the first of the month during the twentieth century (1 Jan 1901 to 31 Dec 2000)?I provide a brute force solution exploiting the date/time part of the .NET api to check all 1200 1st of the month.

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Project Euler 16: The sum of digits in 2^1000

Saturday, December 18, 2010

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Given problem 16 of Project Euler which reads What is the sum of the digits of the number 21000?I exploit the BigInteger class in .NET 4.0 which makes it easy to operate on large integers, and thereby makes it a matter of slicing up the big number.

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Project Euler 13: Sum of 50-digit numbers

Tuesday, December 7, 2010

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Problem 13 of Project Euler reads: Work out the first ten digits of the sum of the following one-hundred 50-digit numbersWith the development of .NET 4.0 you can make a short cut and the solution becomes rather trivial as I am about to show you.

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Stopwatch – a timing function in C#

Wednesday, December 1, 2010

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Recently while seeking inspiration, I found a small function in the .net api called StopWatch. It was exactly what I have been looking for. It is placed under System.Diagnostics.Stopwatch Until now I have made my timed my solution algorithms using multiple timestamp variables, but I have come to realise that the StopWatch is exactly what […]

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