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# The Computer Language Shootout
# http://shootout.alioth.debian.org/
# Contributed by Sokolov Yura
# Modified by Ryan Williams
def fannkuch(n)
maxFlips, m, r, check = 0, n-1, n, 0
count = (1..n).to_a
perm = (1..n).to_a
while true
if check < 30
puts "#{perm}"
check += 1
end
while r != 1:
count[r-1] = r
r -= 1
end
if perm[0] != 1 and perm[m] != n
perml = perm.clone #.dup
flips = 0
while (k = perml.first ) != 1
perml = perml.slice!(0, k).reverse + perml
flips += 1
end
maxFlips = flips if flips > maxFlips
end
while true
if r==n : return maxFlips end
perm.insert r,perm.shift
break if (count[r] -= 1) > 0
r += 1
end
end
end
N = (ARGV[0] || 1).to_i
puts "Pfannkuchen(#{N}) = #{fannkuch(N)}"
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