# HG changeset patch
# User Dominic Cleal <dominic@computerkb.co.uk>
# Date 1228158715 0
# Node ID 49c96972949d647f1734109dbda916fc81ce319e
# Parent  836a4ccbcbae34b2dbfff403a26db0cd7430e514
#50 rewrite of solution

diff -r 836a4ccbcbae -r 49c96972949d problem50.py
--- a/problem50.py	Mon Dec 01 13:14:53 2008 +0000
+++ b/problem50.py	Mon Dec 01 19:11:55 2008 +0000
@@ -1,35 +1,27 @@
-import math
-
-def count(i, min):
-	for a in range(0, len(p) - min):
-		t = 0
-		for b in range(a, len(p)):
-			t += p[b]
-			if t == i:
-				return b - a + 1
-			if t > i:
-				break
-	return False
+import primes
 
-cmax = 0
-imax = 0
-p = [ 2 ]
-i = 3
-while i < 1000:
-	isp = True
-	max = int(math.floor(math.sqrt(i)))
-	for t in p[1:]:
-		if t > max:
+def search(pmax):
+	cur = { }
+	max = { }
+	s = primes.testsieve()
+	for p in s.sieve():
+		if p > pmax:
 			break
-		if i % t == 0:
-			isp = False
-			break
-	if isp:
-		p.append(i)
-		c = count(i, cmax)
-		if not c == False and c > cmax:
-			cmax = c
-			imax = i
-			print "New max %d with %d conseq" % (i, c)
-	i += 2
+		if p not in cur:
+			cur[p] = (0, 0)
+		todel = []
+		for i in cur:
+			cur[i] = (cur[i][0] + 1, cur[i][1] + p)
+			if cur[i][1] > pmax:
+				todel.append(i)
+			elif s.isprime(cur[i][1]):
+				max[i] = cur[i]
+		for i in todel:
+			del cur[i]
+	retmax = None
+	for i in max:
+		if retmax is None or max[i][0] > retmax[0]:
+			retmax = max[i]
+	return retmax
 
+print "Max conseq has %d terms, totalling %d" % search(1000000)