DAP AN THI HSG TPHCM NAM 2011 BAI 3

{Bai3: Bien Doi
Dau tien, mot day gom mot so 1 duoc nhap vao may tinh. Tai moi buoc tiep theo,
may tinh bien doi dong thoi moi chu so 0 trong day thanh 10 va moi chu so 1
thanh day 01. Nhu vay sau buoc dau ta co day 01; sau buoc thu 2 ta co day: 1001
sau buoc 3 ta co: 01101001 va cu tiep tuc nhu the
Nhiem vu: Tim xem co bao nhieu cap so 0 lien tiep xuat hien trong day sau n buoc
Du lieu: Vao tu tap tin biendoi.inp, gom 2 so nguyen duong n (0Ket qua: Ghi ra tap tin van ban biendoi.out so nguyen duong duy nhat la so cap so
0 lien tiep xuat hien sau n buoc bien doi
biendoi.int la 2 thi biendoi.out la 1
biendoi.int la 3 thi biendoi.out la 1}
program biendoi;
uses crt;
var n,sm,kq,i:integer;
fi,fo:text;

begin
clrscr;



assign(fi,`d:iendoi.inp`);
assign(fo,`d:iendoi.out`);
reset(fi);
read(fi,n);
rewrite(fo);
if (n<0) and (n>20) then
begin
writeln(fo,`N=`,n,` khong nam trong pham vi tu 1 den 20`);
exit;
end;
sm:=1;
if n=1 then kq:=0
else if (n=2) or (n=3) then kq:=1
else if n=4 then kq:=3
else if n=5 then kq:=5
else
begin
for i:=1 to n-5 do
sm:=sm*2;
kq:=sm*5;
end;
write(kq);
write(fo,kq);
close(fi);
close(fo);
readln;
end.