Linked_List

Question

To insert a node at the end of double linked list we need to modify two pointers right??But answer given is one pointer.
can someone clarify?

Answer 1

Assume we have a pointer " LAST " which point to the last pointer

and we know LAST --> next = NULL

we create a new pointer called NEW and add it to end of LL

so we hv to modify following pointers :

LAST --> next = NEW

NEW  --> prev = LAST

NEW  --> next = NULL

Comments

ur approach is correct

but in made easy test series answer given is one only..

I think to insert at the end we are modifying only last->next = new which was null earlier

rest all ,we  are assigning not modifying.

new->next=null and new->prev=last both are assignment instead of modification.

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if it like , how many links are modified in only given LL , i mean if we dont consider NEW node links

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ya...because new node is not there in the list and we are just assiging the value to its data and link part then inserting it at the end so it is added not modified.

if something is already there and we are changing then we are are modifying the pointer.

So, only one pointer is modified which is last->link

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I agree with @cse23