Permutations: Difference between revisions

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@@ Line 1,503: / Line 1,503: @@
 <lang lua>
-local function permutation(a, n)
+local function permutation(a, n, cb)
 	if n == 0 then
+		cb(a)
-		print('{'..table.concat(a, ', ')..'}')
 	else
 		for i = 1, n do
 			a[i], a[n] = a[n], a[i]
-			permutation(a, n - 1)
+			permutation(a, n - 1, cb)
 			a[i], a[n] = a[n], a[i]
 		end
@@ Line 1,515: / Line 1,515: @@
 end
+--Usage
-permutation({1,2,3}, 3)
+local function callback(a)
+	print('{'..table.concat(a, ', ')..'}')
--- {2, 3, 1}
+end
--- {3, 2, 1}
+permutation({1,2,3}, 3, callback)
--- {3, 1, 2}
--- {1, 3, 2}
--- {2, 1, 3}
--- {1, 2, 3}
 </lang>
+{{out}}
+<pre>
+{2, 3, 1}
+{3, 2, 1}
+{3, 1, 2}
+{1, 3, 2}
+{2, 1, 3}
+{1, 2, 3}
+</pre>
 =={{header|Mathematica}}==