Tolleranter String-Vergleich

[Florian H]

ok

Delphi-Quellcode:

unit Levenshtein;
//Objeto que calcula la distancia de Levenshtein entre 2 cadenas.
//Alvaro Jeria Madariaga. 04/10/2002
//[e-mail]
interface
uses sysutils, Math;
type
  Tdistance = class(TObject)
  private
    function minimum(a, b, c: Integer): Integer;
  public
    function LD(s, t: string): Integer;
  end;

implementation

function Tdistance.minimum(a, b, c: Integer): Integer;
var mi: Integer;
begin
  mi := a;
  if (b < mi) then
    mi := b;
  if (c < mi) then
    mi := c;
  Result := mi;
end;

function Tdistance.LD(s, t: string): Integer;
var
  d: array of array of Integer;
  n, m, i, j, costo: Integer;
  s_i, t_j: char;
begin
  n := Length(s);
  m := Length(t);
  if (n = 0) then begin
      Result := m;
      Exit;
    end;
  if m = 0 then begin
      Result := n;
      Exit;
    end;
  setlength(d, n + 1, m + 1);
  for i := 0 to n do
    d[i, 0] := i;
  for j := 0 to m do
    d[0, j] := j;
  for i := 1 to n do
    begin
      s_i := s[i];
      for j := 1 to m do
        begin
          t_j := t[j];
          if s_i = t_j then costo := 0 else costo := 1;
          d[i, j] := Minimum(d[i - 1][j] + 1, d[i][j - 1] + 1, d[i -1][j - 1] + costo);
        end;
    end;
  Result := d[n, m];
end;
end.

danke