CHEAT - Chơi bi-a 1 lỗ
Tác giả: ll931110
Ngôn ngữ: Pascal
program CHEAT;
const
fi='';
fo='';
var
f:text;
free:array[1..100000] of boolean;
i,j,n,h,k:longint;
angian:boolean;
procedure xuly;
begin
assign(f,fi);
reset(f);
readln(f,n);
fillchar(free,n,true);
angian:=false;
for i:= 1 to n do
begin
readln(f,k);
free[k]:=false;
if h>k then
for j:= k to h do
if free[j] then
begin
angian:=true;
exit;
end;
h:=k;
end;
close(f);
end;
procedure xuat;
begin
assign(f,fo);
rewrite(f);
if angian=true then write(f,'YES')
else
write(f,'NO');
close(f);
end;
begin {main}
xuly;
xuat;
end.