Data commit

Task/Best-shuffle/Delphi/best-shuffle.delphi

@@ -0,0 +1,138 @@
+program Best_shuffle;
+
+{$APPTYPE CONSOLE}
+
+uses
+  System.SysUtils,
+  System.Generics.Collections;
+
+type
+  TShuffledString = record
+  private
+    original: string;
+    Shuffled: TStringBuilder;
+    ignoredChars: Integer;
+    procedure DetectIgnores;
+    procedure Shuffle;
+    procedure Swap(pos1, pos2: Integer);
+    function TrySwap(pos1, pos2: Integer): Boolean;
+    function GetShuffled: string;
+  public
+    class operator Implicit(convert: string): TShuffledString;
+    constructor Create(Word: string);
+    procedure Free;
+    property Ignored: integer read ignoredChars;
+    property ToString: string read GetShuffled;
+  end;
+
+{ TShuffledString }
+
+procedure TShuffledString.Swap(pos1, pos2: Integer);
+var
+  temp: char;
+begin
+  temp := shuffled[pos1];
+  shuffled[pos1] := shuffled[pos2];
+  shuffled[pos2] := temp;
+end;
+
+function TShuffledString.TrySwap(pos1, pos2: Integer): Boolean;
+begin
+  if (original[pos1] = shuffled[pos2]) or (original[pos2] = shuffled[pos1]) then
+    Exit(false)
+  else
+    Exit(true);
+end;
+
+procedure TShuffledString.Shuffle;
+var
+  length, swaps: Integer;
+  used: TList<Integer>;
+  i, j, k: Integer;
+begin
+  Randomize;
+
+  length := original.Length;
+  used := TList<Integer>.create();
+
+  for i := 0 to length - 1 do
+  begin
+    swaps := 0;
+    while used.Count <= (length - i) do
+    begin
+      j := i + Random(length - 1 - i);
+
+      if (original[i] <> original[j]) and TrySwap(i, j) and (not used.Contains(j)) then
+      begin
+        Swap(i, j);
+        Inc(swaps);
+        break;
+      end
+      else
+        used.Add(j);
+    end;
+
+    if swaps = 0 then
+    begin
+      for k := i downto 0 do
+      begin
+        if TrySwap(i, k) then
+          Swap(i, k);
+      end;
+    end;
+    used.Clear();
+  end;
+  used.Free;
+end;
+
+constructor TShuffledString.Create(Word: string);
+begin
+  original := Word;
+  shuffled := TStringBuilder.create(Word);
+  Shuffle();
+  DetectIgnores();
+end;
+
+procedure TShuffledString.DetectIgnores;
+var
+  ignores, i: Integer;
+begin
+  ignores := 0;
+  for i := 0 to original.Length - 1 do
+  begin
+    if original[i] = shuffled[i] then
+      Inc(ignores);
+  end;
+  ignoredChars := ignores;
+end;
+
+procedure TShuffledString.Free;
+begin
+  Shuffled.Free;
+end;
+
+function TShuffledString.GetShuffled: string;
+begin
+  result := shuffled.ToString();
+end;
+
+class operator TShuffledString.Implicit(convert: string): TShuffledString;
+begin
+  result := TShuffledString.Create(convert);
+end;
+
+var
+  words: array of string;
+  Word: TShuffledString;
+  w: string;
+
+begin
+  words := ['abracadabra', 'seesaw', 'elk', 'grrrrrr', 'up', 'a'];
+  for w in words do
+  begin
+    Word := w;
+    writeln(format('%s, %s, (%d)', [Word.Original, Word.ToString, Word.Ignored]));
+    Word.Free;
+  end;
+  Readln;
+end.