91 lines
2.0 KiB
Lua
91 lines
2.0 KiB
Lua
--[[
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The Great Computer Language Shootout
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http://shootout.alioth.debian.org/
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contributed by Isaac Gouy
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]]
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local bench = script and require(script.Parent.bench_support) or require("bench_support")
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function test()
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local function fannkuch(n)
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local check = 0;
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local perm = {};
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local perm1 = {};
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local count = {};
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local maxPerm = {};
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local maxFlipsCount = 0;
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local m = n - 1;
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for i = 1,n do perm1[i] = i - 1; end
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local r = n;
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while (true) do
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-- write-out the first 30 permutations
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if (check < 30) then
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local s = "";
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for i = 1,n do s = s .. tostring(perm1[i]+1); end
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check = check + 1;
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end
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while (r ~= 1) do count[r] = r; r = r - 1; end
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if (not (perm1[1] == 0 or perm1[m + 1] == m)) then
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for i = 1,n do perm[i] = perm1[i]; end
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local flipsCount = 0;
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local k;
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k = perm[1]
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while (not (k == 0)) do
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local k2 = math.floor((k + 1) / 2);
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for i = 0,k2-1 do
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local temp = perm[i + 1];
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perm[i + 1] = perm[k - i + 1];
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perm[k - i + 1] = temp;
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end
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flipsCount = flipsCount + 1;
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k = perm[1]
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end
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if (flipsCount > maxFlipsCount) then
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maxFlipsCount = flipsCount;
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for i = 1,n do maxPerm[i] = perm1[i]; end
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end
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end
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while (true) do
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if (r == n) then return maxFlipsCount; end
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local perm0 = perm1[1];
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local i = 0;
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while (i < r) do
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local j = i + 1;
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perm1[i + 1] = perm1[j + 1];
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i = j;
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end
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perm1[r + 1] = perm0;
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count[r + 1] = count[r + 1] - 1;
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if (count[r + 1] > 0) then break; end
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r = r + 1;
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end
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end
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return 0
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end
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local n = 8;
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local ret = fannkuch(n);
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local expected = 22;
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if (ret ~= expected) then
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assert(false, "ERROR: bad result: expected " .. expected .. " but got " .. ret);
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end
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end
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bench.runCode(test, "fannkuch")
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