Solved

# Permutation

Posted on 2001-08-20
510 Views
Hi,
I need one routine for permutation in my project as follows.

I want 3 number combination from 1 to 15 numbers. Each combination should be put in a file, one combination per line as follows(comma seperated),

1,2,3
1,9,15
.
.
.

I want all the combinations.

Experts, help me

VeeramaniRaj
0
Question by:veeramani
• 5
• 5
• 4
• +4

LVL 1

Expert Comment

ID: 6405300
Here is some code, just add a button with the following code.

John.

procedure TForm1.Button1Click(Sender: TObject);
var f:textfile;
num1,num2,num3:integer;
begin
assignfile(f,'c:\numbers.csv');
if not fileexists('c:\numbers.csv') then
rewrite(F)
else
append(f);
for num1 := 1 to 15 do
begin
for num2:= 1 to 15 do
begin
for num3:=1 to 15 do
begin
writeln(f,inttostr(num1),',',inttostr(num2),',',inttostr(num3));
end;
end;

end;
closefile(f);
end;
0

LVL 21

Expert Comment

ID: 6405340
veermani do You want include combinations like : 1,1,1 ; 2,2,2 ??
ziolko.
0

LVL 1

Author Comment

ID: 6405364
No, I don't want 1,1,1, even 1,1,2 also. The numbers should not be repeated in the combination.
0

LVL 6

Expert Comment

ID: 6405394
try this for not repeating.

for num1 := 1 to 15 do
begin
for num2:= 1 to 15 do
begin
if num2 <> num1 then begin
for num3:=1 to 15 do
begin
if num3 <> num1 and num3 <> num2 then begin                             writeln(f,inttostr(num1),',',inttostr(num2),',',inttostr(num3));
end;
end;
end;
end;
end;
0

LVL 3

Expert Comment

ID: 6405397
This is a code that permutes any string you give, making all possible permutations. It needs a little modification to insert the commasunit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;

type
TForm1 = class(TForm)
Edit1: TEdit;
ListBox1: TListBox;
procedure Edit1KeyPress(Sender: TObject; var Key: Char);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{\$R *.dfm}

procedure Permute(s:string;sl:TStrings);
var
slbuf:TStringList;
i,j:integer;
begin
if Length(s)=2 then
begin
sl.Clear;
exit;
end;
slbuf:=TStringList.Create();
try
sl.Clear;
for i:=1 to Length(s) do
begin
Permute(Copy(s,1,i-1)+Copy(s,i+1,length(s)),slbuf);
for j:=0 to slbuf.Count-1 do
end;
finally
slbuf.Free;
end;
end;

procedure TForm1.Edit1KeyPress(Sender: TObject; var Key: Char);
begin
if key=#13 then
begin
Permute(Edit1.Text,ListBox1.Items);
end;
end;

end.

0

LVL 1

Expert Comment

ID: 6405449
So you don't want all the combinations.

0

LVL 1

Author Comment

ID: 6405471
Hi Karouri,
Is it working in your computer?
0

LVL 6

Expert Comment

ID: 6405483
Hi veeramani,
is my method work fine for your requirement.

Best Regards,
kotan
0

LVL 1

Author Comment

ID: 6405510
Hi Kotan,
It's working, but repeating
i mean , it gives 1 2 3 as well as 1 3 2

I want unique combinations after sorting
0

LVL 21

Expert Comment

ID: 6405522
for i1:=1 to 15 do
for i2:=i1+1 to 15 do
for i3:=i1 to 15 do
comb:=InttoStr(i1)+','+IntToStr(i2)+','+IntToStr(i3)
0

LVL 21

Expert Comment

ID: 6405528
for i1:=1 to 15 do
for i2:=1 to 15 do
if i2<>i1 then
for i3:=i1 to 15 do
comb:=InttoStr(i1)+','+IntToStr(i2)+','+IntToStr(i3)
0

LVL 21

Expert Comment

ID: 6405532
ooops sorry second comment is ok so ignore first one :-))
ziolko.
0

LVL 6

Expert Comment

ID: 6405561
I think should be like this,

for i1:=1 to 15 do
for i2:=i1+1 to 15 do
for i3:=i2+1 to 15 do
comb:=InttoStr(i1)+','+IntToStr(i2)+','+IntToStr(i3)
0

LVL 1

Author Comment

ID: 6405565
All restricted to only limit of three, but, if i change it to some 6 or 7, it won't work. I want a algorithamic approch.

Regards,

veeramaniraj
0

LVL 1

Expert Comment

ID: 6405623
Surely if you want unique then all you increment is the outside value. Like this.

procedure TForm1.Button1Click(Sender: TObject);
var f:textfile;
num1,num2,num3:integer;
begin
assignfile(f,'c:\numbers.csv');
if not fileexists('c:\numbers.csv') then
rewrite(F)
else
append(f);
num1 := 1;
num2:= 2;

for num3:=3 to 15 do
begin
writeln(f,inttostr(num1),',',inttostr(num2),',',inttostr(num3));
end;

closefile(f);
end;
0

LVL 1

Expert Comment

ID: 6405624
Surely if you want unique then all you increment is the outside value. Like this.

procedure TForm1.Button1Click(Sender: TObject);
var f:textfile;
num1,num2,num3:integer;
begin
assignfile(f,'c:\numbers.csv');
if not fileexists('c:\numbers.csv') then
rewrite(F)
else
append(f);
num1 := 1;
num2:= 2;

for num3:=3 to 15 do
begin
writeln(f,inttostr(num1),',',inttostr(num2),',',inttostr(num3));
end;

closefile(f);
end;
0

LVL 3

Expert Comment

ID: 6405759
my method is working on my computer, but the following problem may have happened to you:
It uses recursion in a memory intensive way. I will post another method that uses much less memory later..
0

LVL 6

Expert Comment

ID: 6406781
This is a solution using recursive method, may be there are some syntax error. Because I am new to Delphi.

procedure permute(r: Integer, n: Integer)
strP: string[r];
begin
recurpermute(r, n, 0, strP);
end;

procedure recurpermute(r: Integer, n: Integer, loop: Integer, strP: string)
i, c: Integer;
begin
for i := loop + 1 to n do
begin
strP[r] := i;
if r <> 1 then
begin
recurpermute(r - 1, n, i, strP);
end else
begin
for c := strP[0] downto 1 do
begin
write(f, strP[c]);
if c <> 1 then
write(', ')
else
writeln();
end;
end;
end
end;

Hope this helps.

Best Regard,
kotan
0

LVL 3

Expert Comment

ID: 6406855
I am sorry, I think I have overlooked the 'combinations not permutations' question..
0

LVL 10

Accepted Solution

Jacco earned 100 total points
ID: 6407227
These are some routines I used for generating permutations. The algoritm uses string representing binary numbers. It is a non-recursive routine since recusion eats stack space. The starting string must have all 1 to the right of the string.

000000000000111 is the first

NextPerm permutes to the next state
CheckPerm checks whether a next permutation can be made

The routine can do something more of which I stripped some code. It can permute groups of bits inside the string. For example you can have two groups of six bits starting out as

000111000111

NextPerm(s, 1, 6) permutes the first part
NextPerm(s, 7, 6) permutes the second part

This way you can combine the statistics for 3 out of 6 with another 3 out of six. Maybe this is usefull in you code as well.

MakeInit is used when using groups.

When using groups you have to call NextPerm hierarchically

Hope this works for you

Regards Jacco

procedure MakeInit(var s: String; iStart, iLength: Integer);
var
SubStr: String;
iPos: Integer;
TempStr: String;
begin
TempStr := '';
SubStr := Copy(s,iStart,iLength);
for iPos:=1 to Length(SubStr) do
if SubStr[iPos]='1' then TempStr := TempStr + '1';
for iPos:=Length(TempStr)+1 to iLength do
TempStr := '0' + TempStr;
Delete(s,iStart,iLength);
Insert(TempStr,s,iStart);
end;

function NextPerm(var s: String; iStart, iLength: Integer): Boolean;
var
SubStr: String;
iPos1,iPos2: Integer;
begin
Result := False;
SubStr := Copy(s,iStart,iLength);
if Pos('0',SubStr)=0 then Exit;
iPos1 := Pos('01',SubStr);
iPos2 := Pos('1',SubStr);
if iPos1<>0 then begin
Delete(SubStr,iPos1,2);
Insert('10',SubStr,iPos1);
if (iPos2 <> 0) and (iPos2 < iPos1) then begin
MakeInit(SubStr,1,iPos1-1);
end;
Delete(s,iStart,iLength);
Insert(SubStr,s,iStart);
Result := True;
end;
end;

function CheckPerm(s: String; iStart, iLength: Integer): Boolean;
var
SubStr: String;
begin
Result := False;
SubStr := Copy(s,iStart,iLength);
if Pos('0',SubStr)=0 then Exit;
if Pos('01',SubStr)=0 then Exit;
Result := True;
end;

procedure OutputLine(var F: TextFile; const s: string);
var
i: Integer;
b: Boolean;
begin
b := True;
for i := 1 to Length(s) do
if s[i] = '1' then
begin
if b then
b := False
else
Write(F, ',');
Write(F, IntToStr(i));
end;
WriteLn(F);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
s: String;
i: Integer;
t1: TDateTime;
F: TextFile;
begin
AssignFile(F, 'c:\permutations.csv');
try
Rewrite(F);
s := '000000000000111';
i := 0;
t1 := Now;
while CheckPerm(s,1,15) do begin
OutputLine(F, s);
NextPerm(s,1,15);
OutputLine(F, s);
Inc(i);
end;
OutputLine(F, s);
t1 := Now - t1;
Memo1.Lines.Add(IntToStr(i) + ' perms in second: '+FloatToStrF(t1*60*60*24,ffFixed,15,2));
finally
CloseFile(F);
end;
end;
0

LVL 10

Expert Comment

ID: 6407271
Sorry you should delete the second OutputLine in the last procedure

Regards
0

LVL 10

Expert Comment

ID: 6407281
Here is the correct Button1Click

procedure TForm1.Button1Click(Sender: TObject);
var
s: String;
i: Integer;
t1: TDateTime;
F: TextFile;
begin
AssignFile(F, 'c:\permutations.csv');
try
Rewrite(F);
s := '000000000000111';
i := 0;
t1 := Now;
while CheckPerm(s,1,15) do begin
OutputLine(F, s);
NextPerm(s,1,15);
Inc(i);
end;
OutputLine(F, s);
t1 := Now - t1;
Memo1.Lines.Add(IntToStr(i) + ' perms in second: '+FloatToStrF(t1*60*60*24,ffFixed,15,2));
finally
CloseFile(F);
end;
end;
0

LVL 3

Expert Comment

ID: 6407492
This is a Complete Pascal7 program to make permutation of  given numbers!
It can be easily converted to delphi!

Hope this helps!
VSF
www.victory.hpg.com.br

Program permutations;

Uses Crt;

Type hold_em_here = Array[1..15] of Integer;

Var  numbers,combs,bot2a : Integer;
ans,top,bot1,bot2b : Real;
hold_Array : hold_em_here;

Function permutate_this(number1 : Integer) : Real;
Var i : Integer;
a : Real;
begin
a := number1;
For i := (number1 - 1) doWNto 1 do a := a  * i;
permutate_this := a;
end;

Procedure input_numbers(Var hold_Array : hold_em_here; counter : Integer);
Var i,j : Integer;
begin
For i := 1 to counter do begin
Write(' Input #',i:2,': ');
hold_Array[i] := j;
end;
end;

Procedure show_numbers(hold_Array : hold_em_here; counter : Integer);
Var i,j : Integer;
begin
WriteLN;
Write('Array looks like this: ');
For i := 1 to counter do Write(hold_Array[i]:3);
WriteLN
end;

begin
ClrScr;
WriteLN;
WriteLN('  Permutations');
WriteLN;
Write('     Enter number of digits (1-15): ');
Write('Enter number in combination (2-10): ');
top := permutate_this(numbers);
bot1 := permutate_this(combs);
bot2a := numbers - combs;
bot2b := permutate_this(bot2a);
ans := top/(bot1*bot2b);
WriteLN('   total permutations For above is: ',ans:3:0);
WriteLN;
input_numbers(hold_Array,numbers);
show_numbers(hold_Array,numbers);
END.
0

LVL 10

Expert Comment

ID: 6413334
Veeramani? Are you still with us?

Jacco
0

LVL 1

Author Comment

ID: 6413562
Listening.....
0

LVL 10

Expert Comment

ID: 6414559
Are you going to grade the question?

Regards Jacco
0

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