PRDCEDURE: DOUBINS (L, R, M, X)
1. [Create New Empty Node]
NEW<- NODE
2. [Copy information field]
INFO (NEW) <- X
3. [Insert into an empty list]
If R=NULL
then LPTR (NEW)<-RPTR(NULL) <-NULL
L<-R<-NEW
Return
4. [Is left most insertion ?]
If M = L
then LPTR (NEW)<-NULL
RPTR (NEW) <- M
LPTR (M)<- NEW
L <- NEW
Return
5. [Insert in middle]
LPTR (NEW)<- LPTR (M)
RPTR (NEW)<- M
LPTR (M)<- NEW
RPTR (LPTR (NEW))<- NEW
Return
REVERSE_TRAVERSE
