Here's my code:
(I looked for the walls like as mirrors)


{H+}{N+}
.Program N1258;
.
.var
.   w,d           :integer;
.   x1,x0,y1,y0   :integer;
.   way           :string;
.   leng          :integer;
.   BF,LR         :integer;
.   hor,ver       :integer;
.   i,j           :integer;
.   lastBF,lastLR,firstBF,firstLR :char;
.   Lx,Ly,Lzag    :extended;
.
.BEGIN
.   readln(w,d);
.   If (w=0)or(d=0)then
.   begin
.      writeln('0.0000');
.      Halt;
.   End;
.   {initialisation}
.   readln(x0,y0);
.   readln(x1,y1);
.   readln(way);

.   If way='' then
.   Begin
.      writeln((sqrt(sqr(x0-x1)+sqr(y0-y1))):0:4);
.      Halt;
.   End;

.   Leng:=length(way);


.   firstBF:='0';
.   firstLR:='0';

.   {finding last and first of B and F}
.   {finding number of B and F}
.   For i:=1 to leng do
.      If (way[i]='B')or(way[i]='F')then
.      Begin
.         lastBF:=way[i];
.         IF firstBF='0' then
.            firstBF:=way[i];
.         inc(BF);
.      End;

.   {finding last and first of L and R}
.   {finding number of  L and R}
.   For i:=1 to leng do
.      If (way[i]='L')or(way[i]='R')then
.      Begin
.         lastLR:=way[i];
.         IF firstLR='0' then
.            firstLR:=way[i];
.         inc(LR);
.      End;

.   {finding length of route}
.   IF firstBF='B' then
.      Ly:=d-y0
.       else Ly:=y0;
.   IF firstLR='L' then
.      Lx:=x0
.       else Lx:=w-x0;
.   IF lastBF='B' then
.      Ly:=Ly+d-y1
.       else Ly:=Ly+y1;
.   IF lastLR='L' then
.      Lx:=Lx+x1
.       else Lx:=Lx+w-x1;
.   Lx:=Lx+w*(LR-1);
.   Ly:=Ly+d*(BF-1);
.   Lzag:=sqrt(Lx*Lx+Ly*Ly);
.   Writeln(Lzag:0:4);
.END.

PS. Ican't see the difference between AC code from forum.

Edited by author 20.08.2005 02:34

It's not so simple as you think, but simple in real.
Try this test
4 6
2 1
2 5
R
---
Your answer is 4.0000, but write answer is 5.6569

Thanks, good test!

Thanke you, Ozone, you realy helped me!