Title: get Permutations of a String?
{
Definition: Permutation
A permutation is an arrangement of n objects, arranged in groups of size r
without repetition where order is important.
P(n,r) = n! / (n-r)!
Example: Find all two-letter permutations of the letters "ABC"
n = ABC
r = 2
Output: AB AC BA BC CA CB
}
{
Definition: Permutation
Eine Permutation ist eine Anordnung von n Objekten ohne Wiederholung.
Dabei spielt die Reihenfolge der Elemente in den Mengen keine Rolle.
P(n,r) = n! / (n-r)!
Beispiel: Finde alle 2-Buchstaben Kombinationen von "ABC"
n = ABC
r = 2
Ergebnis: AB AC BA BC CA CB
}
{
The following is a console Program:
Choose File, New, Console Application
}
program Permute;
{$APPTYPE CONSOLE}
uses SysUtils;
var
R, Slen: Integer;
procedure P(var A: string; B: string);
var
J: Word;
C, D: string;
begin
{ P(N,N) R=Slen }
if Length(B) = SLen - R then
begin
Write(' {' + A + '} '); {Per++}
end
else
for J := 1 to Length(B) do
begin
C := B;
D := A + C[J];
Delete(C, J, 1);
P(D, C);
end;
end;
var
Q, S, S2: string;
begin
S := ' ';
S2 := ' ';
while (S '') and (S2 '') do
begin
Writeln('');
Writeln('');
Write('P(N,R) N=? : ');
ReadLn(S);
SLen := Length(S);
Write('P(N,R) R=? : ');
ReadLn(S2);
if s2 '' then R := StrToInt(S2);
Writeln('');
Q := '';
P(Q, S);
end;
end.