Help me PLEASE!
What's wrong with it?
I always get WA.

program timus_1021;
var
 t1, t2:array [1..50000] of longint;
 j, i, l1, l2, l:longint;
 wyn:boolean;
begin
 readln (l1);
 for i:=1 to l1 do
  readln (t1[i]);
 readln (l2);
 for i:=1 to l2 do
  readln (t2[i]);
 i:=0;
 wyn:=false;
 repeat
  inc (i);
  j:=l2;
  while t1[i]+t2[j]<10000 do
   dec (j);
  if t1[i]+t2[j]=10000 then wyn:=true;
 until i=l1;
 if wyn then writeln ('YES')
  else writeln ('NO')
end.

> Help me PLEASE!
> What's wrong with it?
> I always get WA.

>   while t1[i]+t2[j]<10000 do
>    dec (j);
>   if t1[i]+t2[j]=10000 then wyn:=true;
...

  Did you sort the sequence ? No You didn't, So why do You expect
that after
  "t1[i]+t2[j]<10000"
can't be
  "t1[i]+t2[j]>10000"
and then
  "t1[i]+t2[j]<10000" again ?

You must either sort the arrays before, or change the condition
in "while", to check ALL combinations.

var
say,say2:array [1..10000] of integer;
n,k,i,m,s:longint;
begin
 s:=0;
 readln(n);
    repeat
    k:=k+1;
    readln(say[k]);
    until k=n;
 readln(m);
    repeat
    i:=i+1;
    readln(say2[i]);
    until i=m;
 i:=0;
 k:=0;
    repeat
    k:=k+1;
       repeat
       i:=i+1;
       if (say[k]+say2[i])=10000  then s:=1;
       until s=1;
    until s=1;
  if s=1  then writeln('yes')
  else writeln('no');
 end.