DSA · Theory

LINKED LIST REVERSE

Theory

614/810

LINKED LIST REVERSE

LINKED LIST REVERSE is a DSA topic. In plain words you use it for a ticket queue node in a counter. Don’t start with a slogan — start with that picture.

Smallest example: head → next → …. Type it, run it, and say what you see. If you can do that from memory, you know LINKED LIST REVERSE.

From the example next to this theory: LINKED LIST REVERSE — a linked list chains nodes with next pointers instead of contiguous indexes.

Trap — losing the next pointer on delete. Fix that before you talk about advanced DSA.

Viva — what is LINKED LIST REVERSE? Then show head → next → …. Then name the trap.

Diagram

  [10] → [20] → [30] → /
   head              tail

Exam tip

What is LINKED LIST REVERSE? Show this: head → next → …. Trap: losing the next pointer on delete.

Example

class Node:
    def __init__(self, val, next=None):
        self.val = val
        self.next = next

head = Node(1, Node(2, Node(3)))
cur = head
while cur:
    print(cur.val, end=" -> " if cur.next else "\n")
    cur = cur.next

LINKED LIST REVERSE — a linked list chains nodes with next pointers instead of contiguous indexes.

Short notes

DefLINKED LIST REVERSE — a ticket queue node in a counter.
Rulehead → next → …
Traplosing the next pointer on delete
Usea counter

DSA · Theory

LINKED LIST REVERSE

← All stacks

Theory

614/810

LINKED LIST REVERSE

LINKED LIST REVERSE is a DSA topic. In plain words you use it for a ticket queue node in a counter. Don’t start with a slogan — start with that picture.

Smallest example: head → next → …. Type it, run it, and say what you see. If you can do that from memory, you know LINKED LIST REVERSE.

From the example next to this theory: LINKED LIST REVERSE — a linked list chains nodes with next pointers instead of contiguous indexes.

Trap — losing the next pointer on delete. Fix that before you talk about advanced DSA.

Viva — what is LINKED LIST REVERSE? Then show head → next → …. Then name the trap.

Diagram

  [10] → [20] → [30] → /
   head              tail

Exam tip

What is LINKED LIST REVERSE? Show this: head → next → …. Trap: losing the next pointer on delete.

Example

class Node:
    def __init__(self, val, next=None):
        self.val = val
        self.next = next

head = Node(1, Node(2, Node(3)))
cur = head
while cur:
    print(cur.val, end=" -> " if cur.next else "\n")
    cur = cur.next

LINKED LIST REVERSE — a linked list chains nodes with next pointers instead of contiguous indexes.

Short notes

DefLINKED LIST REVERSE — a ticket queue node in a counter.
Rulehead → next → …
Traplosing the next pointer on delete
Usea counter

LINKED LIST REVERSE

Example

Short notes

Questions

LINKED LIST REVERSE

Example

Short notes

Questions