Comments on: Project Euler 39 http://www.thattommyhall.com/2008/04/12/project-euler-39/ A Random Walk Through Idea Space Tue, 06 Jan 2009 23:31:11 +0000 http://wordpress.org/?v=2.2.2 By: tom http://www.thattommyhall.com/2008/04/12/project-euler-39/#comment-706 tom Mon, 14 Apr 2008 13:32:21 +0000 http://www.thattommyhall.com/2008/04/12/project-euler-39/#comment-706 http://paste.bradleygill.com/index.php?paste_id=238 http://paste.bradleygill.com/index.php?paste_id=238

]]> By: ejs http://www.thattommyhall.com/2008/04/12/project-euler-39/#comment-704 ejs Mon, 14 Apr 2008 11:18:11 +0000 http://www.thattommyhall.com/2008/04/12/project-euler-39/#comment-704 While I don't have the code I used I remember solving it far faster using brute force. After 10 min playing this is what I think I had (hoping the indentation works): import math from eulerhelpers import timed @timed def solve39(cap=1000): result = [0] * (cap+1) for b in xrange(1, cap/2): for c in xrange(1, min(b, cap/2-b)+1): a = math.sqrt(b**2 + c**2) if a+b+c > cap: break if not a%1: result[int(a)+b+c] += 1 if not b%(cap/20): print b, yield print max((i, e) for e, i in enumerate(result)) On my computer, without psyco, it completes in just over 0.1 seconds or about 7 times longer than your more mathematical code. I stopped there thinking it was enough. While I don’t have the code I used I remember solving it far faster using brute force. After 10 min playing this is what I think I had (hoping the indentation works):

import math
from eulerhelpers import timed

@timed
def solve39(cap=1000):
result = [0] * (cap+1)
for b in xrange(1, cap/2):
for c in xrange(1, min(b, cap/2-b)+1):
a = math.sqrt(b**2 + c**2)
if a+b+c > cap:
break
if not a%1:
result[int(a)+b+c] += 1
if not b%(cap/20):
print b,
yield
print max((i, e) for e, i in enumerate(result))

On my computer, without psyco, it completes in just over 0.1 seconds or about 7 times longer than your more mathematical code. I stopped there thinking it was enough.

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