Created
June 12, 2015 22:36
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def dense(n) | |
s = n.to_s(2) | |
c = 0 | |
s.length.times \ | |
{ | |
|i| | |
c += s[i, 1].to_i | |
} | |
return c.to_f / s.length | |
end | |
def f(n) | |
n1 = n | |
c = 0 | |
m = 0 | |
while (n != 1 && n >= n1) | |
n = n * 3 + 1 if (n.odd?) | |
n /= 2 while (n.even?) | |
m = [m, n].max | |
c += 1 | |
end | |
return {'w' => widthdiff(m, n1), 'c' => c, 'd' => (0.5 - dense(n1)).abs} | |
end | |
def long(m) | |
l = [{'n' => 1, 'p' => 0}.merge(f(1))] | |
loop \ | |
{ | |
l = l.sort_by { |x| [x['w'], x['d']] }.reverse | |
break if (l[0]['w'] >= m) | |
x = l.delete_at(rand([l.size, 2].min)) | |
p2 = x['p'] + 1 | |
n2 = x['n'] + 2 ** p2 | |
x1 = x.dup | |
x1['p'] = p2 | |
l << x1 | |
x2 = {'n' => n2, 'p' => p2}.merge(f(n2)) | |
l << x2 | |
} | |
l.sort_by! { |x| -x['c'] } | |
return l.first, l.size | |
end | |
def widthdiff(a, b) | |
a.to_s(2).length - b.to_s(2).length | |
end | |
def two(p) | |
x, c = long(p) | |
a = x['n'] | |
a1 = a | |
ns = a.to_s(2) | |
b = ('1' + ns[2..-1]).to_i(2) | |
b1 = b | |
mx = ma = mb = 0 | |
m = nil | |
while (b != 1 && b >= b1) | |
a = a * 3 + 1 if (a.odd?) | |
a /= 2 while (a.even?) | |
b = b * 3 + 1 if (b.odd?) | |
b /= 2 while (b.even?) | |
m = widthdiff(a, b).abs | |
mx = [m, mx].max | |
ma = [a, ma].max | |
mb = [b, mb].max | |
end | |
return mx, widthdiff(ma, a1), widthdiff(mb, b1), c | |
end | |
(1..1000).each \ | |
{ | |
|p| | |
puts([p, two(p)].join("\t")) | |
$stdout.flush | |
} | |
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