Created
October 22, 2012 18:42
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Lua set permutations of N iterator with coroutines
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local table = require 'table' | |
function permutations(N) | |
local level, set, co = -1, {}, nil | |
for i = 1, N do set[i] = 0 end | |
co = coroutine.create(function () permute(set, level, N, 1) end) | |
return function () | |
local _, p = coroutine.resume(co) | |
return p | |
end | |
end | |
function permute(set, level, N, k) | |
level = level + 1 | |
set[k] = level | |
if level == N then | |
coroutine.yield(set) | |
else | |
for i = 1, N do | |
if set[i] == 0 then | |
permute(set, level, N, i) | |
end | |
end | |
end | |
level = level - 1 | |
set[k] = 0 | |
end | |
return permutations |
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local table = require 'table' | |
local permutations = require 'permutations' | |
for p in permutations(n) do | |
print(table.concat(p, ' ')) | |
end |
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