I get WA in 1 test, why? This solution right at the least for N from 4 to 16.

var
  q, w, r, e : integer;
begin
readln( r);
e := r mod 12;

if (e = 8) or (e = 9) or (e = 3) then
  begin
  w := 6;
  for q := 1 to r div 2 do
    begin
      if w > r then w := 2;
      writeln( q, ' ', w);
      inc( w, 2)
    end;
  end
else
  begin
  w := 2;
  for q := 1 to r div 2 do
    begin
      writeln( q, ' ', w);
      inc( w, 2)
    end
  end;

w := 1;
for q := (r div 2) + 1 to r do
  begin
    writeln( q, ' ', w);
    inc( w, 2);
  end
end.


Edited by author 02.04.2007 13:30

First test is 8.
your output:

1 6
2 8
3 2
4 4
5 1
6 3
7 5
8 7

Look:
000000+0
0000+000
00+00000
+0000000
000+0000
0+000000
0000000+
00000+00

8 7 and 3 2 placed on one 45 degrees line (diagonal).
Result: wrong answer.

Good luck!