### About this page

This is where I put my solutions (or work towards solutions) to Project Euler problems. The problems are something I do in my spare time, so this will not be frequently updated.

I tend to use python for solving these problems, because it's just so quick to write.

### Prime numbers

For many of these problems it's useful to have a list of prime numbers. The primes below are listed are here.

The code for finding these primes is:

flags = [] limit = 1000000 for i in range(0,limit): flags.append(i>1) for i in range(2,limit): if flags[i]==True: j = i while j<limit: j = j+i if j<limit: flags[j] = False for i in range(2,limit): if flags[i]: print i

To read the primes into a list:

primes_file = open('../primes/primes.txt') primes = [] for p in primes_file.read().split('\n'): primes.append(int(p))

### Stopwatch

Just for fun I time how long my solutions take. I place the following snippets before and after the main code:

import time time_0 = time.time() ... time_1 = time.time() print 'That took %.0fms'%(1000*(time_1-time_0))