Data commit

Task/Permutations/Delphi/permutations.delphi

@@ -0,0 +1,58 @@
+program TestPermutations;
+
+{$APPTYPE CONSOLE}
+
+type
+  TItem = Integer;                // declare ordinal type for array item
+  TArray = array[0..3] of TItem;
+
+const
+  Source: TArray = (1, 2, 3, 4);
+
+procedure Permutation(K: Integer; var A: TArray);
+var
+  I, J: Integer;
+  Tmp: TItem;
+
+begin
+  for I:= Low(A) + 1 to High(A) + 1 do begin
+    J:= K mod I;
+    Tmp:= A[J];
+    A[J]:= A[I - 1];
+    A[I - 1]:= Tmp;
+    K:= K div I;
+  end;
+end;
+
+var
+  A: TArray;
+  I, K, Count: Integer;
+  S, S1, S2: ShortString;
+
+begin
+  Count:= 1;
+  I:= Length(A);
+  while I > 1 do begin
+    Count:= Count * I;
+    Dec(I);
+  end;
+
+  S:= '';
+  for K:= 0 to Count - 1 do begin
+    A:= Source;
+    Permutation(K, A);
+    S1:= '';
+    for I:= Low(A) to High(A) do begin
+      Str(A[I]:1, S2);
+      S1:= S1 + S2;
+    end;
+    S:= S + '  ' + S1;
+    if Length(S) > 40 then begin
+      Writeln(S);
+      S:= '';
+    end;
+  end;
+
+  if Length(S) > 0 then Writeln(S);
+  Readln;
+end.