Đề thi Toán - Tin học trong nhà trường (Bài 52)

Bài 52/2001 - Xác định các tứ giác đồng hồ trong ma trận
(Dành cho học sinh THCS và PTTH)
uses crt;
var s,n,i,k,j,a1,a2,b1,b2:integer;
chon,mau:byte;
a:array[1..100,1..100]of integer;
{----------------------------}
procedure nhap;
begin
write(`nhap n>=2:`);readln(n);
for i:=1 to n do
for j:=1 to n do
begin
write(`nhap a[`,i,`j]:`);
readln(a[i,j]);
end;
end;
{----------------------}
procedure tinh;
begin
clrscr;
nhap;
s:=0;
for i:=1 to n-1 do
for j:=1 to n-1 do
if ((a[i,j] or((a[i,j+1] or((a[i+1,j+1] or((a[i+1,j] then inc(s);
writeln;
writeln;
writeln;
writeln(`So luong tu giac dong ho la:`,s);
readln;
end;
{-----------------}
procedure max;
var t:integer;
begin
writeln(`Nhap n>=2:`);readln(n);
i:=1;
a1:=1;a2:=n;
b1:=1;b2:=n;
mau:=0;
t:=0;
while i<=n*n do
begin
for k:=a1 to a2 do
begin
a[b1,k]:=i;
gotoxy(5*k,b1);
inc(mau);
if mau>15 then mau:=1;
textcolor(mau);
write(i);
delay(70);inc(i);
end;
for k:=b1+1 to b2+t do
begin
a[k,a2]:=i;
gotoxy(5*(a2),k);
inc(mau);
if mau>15 then
mau:=1;
textcolor(mau);
write(i);
delay(70);
inc(i);
end;
for k:=b2+t downto b1+1 do
begin
a[k,b2]:=i;
gotoxy(5*(b2-1),k);
inc(mau);
if mau>15 then mau:=1;
textcolor(mau);
write(i);
delay(70);
inc(i);
end;
for k:=a2-2 downto a1 do
begin
a[b1+1,k]:=i;
gotoxy(5*k,b1+1);
inc(mau);
textcolor(mau);
write(i);
delay(70);
inc(i);
end;
dec(a2,2);
dec(b2,2);
inc(t,2);
inc(b1,2);
end;
if n>2 then s:=3*(n-2) else s:=1;
writeln;writeln;
writeln(`Bang dong ho max`);writeln;
writeln(`Voi ma tran vuong cap `,n,`thi so luong tu giac dong ho lon nhat la:`,s);
readln;
End;
{------------------}
procedure min;
begin
clrscr;
writeln(`n>=2:`);readln(n);
i:=1;
b1:=1;
while i<=n*n do
begin
for k:=1 to n do
begin
a[