SQL & PL/SQL :: Getting Parent And Leaf Child Along With ID

I've the following data and i need the parent and leaf most child,including their id's

Create table par_chld (id,p_id,c_id) as
(select 1,900,501 from dual union all
select 2,900,502 from dual union all
select 3,900,503 from dual union all
select 4,100,900 from dual union all
select 5,200,900 from dual union all
select 6,300,400 from dual union all
select 7,101,500 from dual union all
select 8,102,500 from dual union all
select 9,103,500 from dual union all
select 10,201,600 from dual union all
select 11,201,601 from dual union all
select 12,201,602 from dual )

In the above data
p_id =100 has c_id 900 , and this 900 acts as a parent which has child 501 , 502 ,503

And the output should be in the following format , Where i don't need the middle level data. I need parent and its leaf child along with the id's of parent and child

Expected output

id_p p_id id_c c_id

4 100 1 501
4 100 2 502
4 100 3 503
5 200 1 501
5 200 2 502
5 200 3 503
6 300 6 400
7 101 7 500
8 102 8 500
9 103 9 500
10 201 10 600
11 201 11 601
12 201 12 602

I tried the following query where i got the p_id,id_c,c_id columns , but unable to get the column id_p

select connect_by_root p_id p_id ,id id_c,c_id
from par_chld
where connect_by_isleaf =1
start with p_id not in (select c_id
from par_chld
where c_id is not null)
connect by nocycle p_id =prior c_id

getting the id_p column as expected above.