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64eccdd9be
Mainly to get rid of one top level directory. But this will also be useful when there are tests of the embedding API.
48 lines
1.3 KiB
Lua
48 lines
1.3 KiB
Lua
-- The Computer Language Benchmarks Game
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-- http://benchmarksgame.alioth.debian.org/
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-- contributed by Mike Pall
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local function fannkuch(n)
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local p, q, s, sign, maxflips, sum = {}, {}, {}, 1, 0, 0
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for i=1,n do p[i] = i; q[i] = i; s[i] = i end
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repeat
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-- Copy and flip.
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local q1 = p[1] -- Cache 1st element.
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if q1 ~= 1 then
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for i=2,n do q[i] = p[i] end -- Work on a copy.
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local flips = 1
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repeat
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local qq = q[q1]
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if qq == 1 then -- ... until 1st element is 1.
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sum = sum + sign*flips
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if flips > maxflips then maxflips = flips end -- New maximum?
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break
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end
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q[q1] = q1
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if q1 >= 4 then
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local i, j = 2, q1 - 1
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repeat q[i], q[j] = q[j], q[i]; i = i + 1; j = j - 1; until i >= j
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end
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q1 = qq; flips = flips + 1
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until false
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end
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-- Permute.
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if sign == 1 then
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p[2], p[1] = p[1], p[2]; sign = -1 -- Rotate 1<-2.
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else
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p[2], p[3] = p[3], p[2]; sign = 1 -- Rotate 1<-2 and 1<-2<-3.
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for i=3,n do
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local sx = s[i]
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if sx ~= 1 then s[i] = sx-1; break end
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if i == n then return sum, maxflips end -- Out of permutations.
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s[i] = i
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-- Rotate 1<-...<-i+1.
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local t = p[1]; for j=1,i do p[j] = p[j+1] end; p[i+1] = t
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end
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end
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until false
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end
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local n = 9
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local sum, flips = fannkuch(n)
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io.write(sum, "\nPfannkuchen(", n, ") = ", flips, "\n") |