Anonymous user
Permutations by swapping: Difference between revisions
m
→{{header|Lua}}: +coroutine version
m (→{{header|Lua}}: +coroutine version) |
|||
Line 1,830:
2 1 4 3
2 1 3 4</pre>
===Coroutine Implementation===
This is adapted from the [https://www.lua.org/pil/9.3.html Lua Book ].
<lang lua>local wrap, yield = coroutine.wrap, coroutine.yield
local function perm(n)
local r = {}
for i=1,n do r[i]=i end
local sign = 1
return wrap(function()
local function swap(m)
if m==0 then
sign = -sign, yield(sign,r)
else
for i=m,1,-1 do
r[i],r[m]=r[m],r[i]
swap(m-1)
r[i],r[m]=r[m],r[i]
end
end
end
swap(n)
end)
end
for sign,r in perm(3) do print(sign,table.unpack(r))end</lang>
=={{header|Mathematica}}==
| |||