I keep getting wa on test 3.
I think my program is quite easy to understand and it's very short. Many thanks if you would love to help me.
Or you can send your solution to me: fujieyun@163.com

Const MaxN = 1000;
      Zero = 1e-8;

Var B1, B2         : Array [1..MaxN,1..2] of LongInt;
    G1, G2         : Array [1..MaxN] of Record
                                          W, Loc : Double;
                                        End;
    N, H, N1, N2, I, J, P   : Integer;

Begin
  ReadLn( H );
  if H = 0
    then Begin
         WriteLn( 'Yes' ); Halt;
         End;
  ReadLn( N1 );
  For I := 1 to N1 do
    Begin
    ReadLn( B1[I,1],B1[I,2] );
    G1[I].W := B1[I,2]-B1[I,1];
    G1[I].Loc := (B1[I,1]+B1[I,2])/2;
    End;

  For I := 2 to H do
    Begin
    ReadLn( N2 ); P := 1;
    FillChar( G2, Sizeof(G2), 0 );
    FillChar( B2, Sizeof(B2), 0 );
    For J := 1 to N2 do
      Begin
      ReadLn(B2[J,1], B2[J,2] );
      G2[J].W := B2[J,2] - B2[J,1];
      G2[J].Loc := (B2[J,1] + B2[J,2])/2;
      if (P<=N1)and(G1[P].Loc < B2[J,1]+Zero)
        then Begin
             WriteLn( 'No' ); Halt;
             End;
      While (P<=N1)and(G1[P].Loc+Zero < B2[J,2]) do
        Begin
        G2[J].Loc := G2[J].Loc + (G1[P].Loc-G2[J].Loc)*G2[J].W/(G1[P].W+G2[J].W);
        G2[J].W := G2[J].W + G1[P].W;
        Inc( P );
        End;
      End;
    if P<=N1
      then Begin
           WriteLn( 'No' ); Halt;
           End;
    B1 := B2; G1 := G2; N1 := N2;
    End;
  WriteLn( 'Yes' );
End.