luah 1.1.0

Unofficial lua impl by HydroRoll-Team.
Documentation 
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-- The Computer Language Benchmarks Game
-- http://benchmarksgame.alioth.debian.org/
-- contributed by Mike Pall

local function fannkuch(n)
    local p, q, s, sign, maxflips, sum = {}, {}, {}, 1, 0, 0
    for i=1,n do p[i] = i; q[i] = i; s[i] = i end
    repeat
      -- Copy and flip.
      local q1 = p[1]				-- Cache 1st element.
      if q1 ~= 1 then
        for i=2,n do q[i] = p[i] end		-- Work on a copy.
        local flips = 1
        repeat
      local qq = q[q1]
      if qq == 1 then				-- ... until 1st element is 1.
        sum = sum + sign*flips
        if flips > maxflips then maxflips = flips end -- New maximum?
        break
      end
      q[q1] = q1
      if q1 >= 4 then
        local i, j = 2, q1 - 1
        repeat q[i], q[j] = q[j], q[i]; i = i + 1; j = j - 1; until i >= j
      end
      q1 = qq; flips = flips + 1
        until false
      end
      -- Permute.
      if sign == 1 then
        p[2], p[1] = p[1], p[2]; sign = -1	-- Rotate 1<-2.
      else
        p[2], p[3] = p[3], p[2]; sign = 1		-- Rotate 1<-2 and 1<-2<-3.
        for i=3,n do
      local sx = s[i]
      if sx ~= 1 then s[i] = sx-1; break end
      if i == n then return sum, maxflips end	-- Out of permutations.
      s[i] = i
      -- Rotate 1<-...<-i+1.
      local t = p[1]; for j=1,i do p[j] = p[j+1] end; p[i+1] = t
        end
      end
    until false
  end
  
  local n = 7 -- input argument
  local sum, flips = fannkuch(n)
  print(sum, "\nPfannkuchen(", n, ") = ", flips, "\n")