# Overview

Usually I try to solve the original challenge from Project Euler first and then tackle its modified version at Hackerrank which is often harder.

I'm a software developer and don't have to mathematical knowledge to solve most of the hard problems.

However, I'm quite good when the solution "just" requires a smart choice of data structures and/or clever use of raw CPU power.

My favorite problem are those with a Dynamic Programming solution.

And of course these little gems that can be somehow applied to real-life computer problems:

Some code snippets are part of several problems. You find a small code collection in my toolbox.

# Heatmap

green problems solve the original Project Euler problem and have a perfect score of 100% at Hackerrank, too.

yellow problems score less than 100% at Hackerrank (but still solve the original problem).

gray problems are already solved but I haven't published my solution yet.

blue problems are solved and there wasn't a Hackerrank version of it at the time I solved it or I didn't care about it because it differed too much.

*Please click on a problem's number to open my solution to that problem:*

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My username at Project Euler is

**stephanbrumme**while it's stbrumme at Hackerrank.

# Most recently solved

June 23, 2017: Problem 225 - Tribonacci non-divisorsJune 22, 2017: Problem 159 - Digital root sums of factorisations

June 21, 2017: Problem 229 - Four Representations using Squares

June 20, 2017: Problem 214 - Totient Chains

June 20, 2017: Problem 165 - Intersections

June 19, 2017: Problem 243 - Resilience

June 19, 2017: Problem 170 - Find the largest 0 to 9 pandigital that can be formed by concatenating products

June 16, 2017: Problem 146 - Investigating a Prime Pattern

June 16, 2017: Problem 164 - Numbers for which no three consecutive digits have a sum greater than a given value

June 15, 2017: Problem 172 - Investigating numbers with few repeated digits

... and 149 more ...