Given this CFG
S->A|t|pCq
S->B|r|^
A->C|q|BA
C->S|p|^
B->m
My try to convert in CNF
Removing Null productions first i.e S->^ and C->^
So after removing
S->A|t|pCq
S->B|r
A->C|q|BA
C->S|p
B->m
Now removing unit productions i.e S->B, A->C, S->A and C->S
S->B gives S->m using B->m
A->C gives A->p using C->p
S->A gives S->q|BA using A->q|BA
C->S gives C->t|pCq|r using S->t|pCq
so adding these productions
S->t|pCq|q|BA
S->r|m
A->q|BA|p
C->p|t|pCq|r
where K->q,U->p
required CNG in CNF is
S->t|UCK|q|BA
S->r|m
A->K|BA|U
C->U|t|UCK|r
R->UC
S->t|RK|q|BA
S->r|m
A->K|BA|U
C->U|t|RK|r
R->UC
K->q
U->p
Is this one correct ?
Removing the Null productions. Some definitions allow S to have a null production, you removed the C production incorrectly. You were supposed to create another production for each production which had a C in the RHS by replacing the C with null.
S->A|t|pCq|pq
S->B|r
A->^|q|BA
C->S|p
B->m
Note: After processing C->^, when you move to S->^, you do not add another C->^ production since that has already been processed. A->^ must be added however (A->C & C->^).
Remove the A -> ^ production
S->A|t|pCq|pq
S->B|r
A->B|q|BA
C->S|p
B->m
Remove A->B and S->B
A->m|q|BA
S->A|m|t|r|pCq|pq
Remove C->S
C->A|p|m|t|r|pCq|pq
Notice how A is also added since S->A hasn't been processed (easier to process it first, I'm just demonstrating a point)
Remove C->A
C->q|p|m|t|r|pCq|pq|BA
Remove S->A
S->q|m|t|r|pCq|pq|BA
Final S->m|r|q|t|pCq|pq|BA A->m|q|BA C->m|p|q|t|r|pCq|pq|BA B->m
Convert to CNF
P->p
Q->q
X->CQ
S->m|r|q|t|PX|PQ|BA
A->m|q|BA
C->m|p|q|t|r|PX|PQ|BA
B->m
Optional:
S->^
EDIT: Oops. I made a mistake. Forgot to add C->r. Sorry ^^'