Revision: 27078
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at May 21, 2010 10:44 by chroto
Initial Code
#!/usr/bin/python
# Project Euler - Problem 14
import math
print "\nProject Euler - Problem 14"
print "For the sequence: \n"
print "n -> n/2 (if n is even)"
print "n -> 3n+1 (if n is odd)\n"
print "Find the longest chain that ends in '1'"
start = 10**6
num = (start/2)
ans = 0
maxcnt=0
while num < start:
x = num
cnt = 1
while x != 1:
if x & 1: x = 3*x + 1 # odd
else: x >>= 1 # even
cnt += 1
if cnt > maxcnt:
ans = num
maxcnt = cnt
num += 1
print ans
Initial URL
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Project Euler - Problem 14
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Python