DSA · Theory

Josephus circle using circular linked list

Theory

709/810

Josephus circle using circular linked list

Josephus circle using circular linked list 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 Josephus circle using circular linked list.

From the example next to this theory: Josephus circle using circular linked list — 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 Josephus circle using circular linked list? Then show head → next → …. Then name the trap.

Diagram

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

Exam tip

What is Josephus circle using circular linked list? 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

Josephus circle using circular linked list — a linked list chains nodes with next pointers instead of contiguous indexes.

Short notes

DefJosephus circle using circular linked list — a ticket queue node in a counter.
Rulehead → next → …
Traplosing the next pointer on delete
Usea counter

DSA · Theory

Josephus circle using circular linked list

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Theory

709/810

Josephus circle using circular linked list

Josephus circle using circular linked list 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 Josephus circle using circular linked list.

From the example next to this theory: Josephus circle using circular linked list — 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 Josephus circle using circular linked list? Then show head → next → …. Then name the trap.

Diagram

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

Exam tip

What is Josephus circle using circular linked list? 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

Josephus circle using circular linked list — a linked list chains nodes with next pointers instead of contiguous indexes.

Short notes

DefJosephus circle using circular linked list — a ticket queue node in a counter.
Rulehead → next → …
Traplosing the next pointer on delete
Usea counter

Josephus circle using circular linked list

Example

Short notes

Questions

Josephus circle using circular linked list

Example

Short notes

Questions