DSA · Theory

LINKED LIST REVERSE

← All stacks

Theory

614/810

LINKED LIST REVERSE

Don’t start LINKED LIST REVERSE with jargon. Start with a ticket queue node. That is the whole point.

Keep LINKED LIST REVERSE small. Neha should finish a ticket queue node in a few lines, not a 40-line dump.

Skip LINKED LIST REVERSE and losing the next pointer on delete shows up in a counter.

Neha ships LINKED LIST REVERSE in a counter. That is the use case worth saying.

Don’t do this with LINKED LIST REVERSE — losing the next pointer on delete. Interviewers spot it in ten seconds.

After LINKED LIST REVERSE, Neha should still remember losing the next pointer on delete.

Close LINKED LIST REVERSE with: “If I skip it, a ticket queue node goes wrong like this: losing the next pointer on delete.”

Diagram

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

Exam tip

For LINKED LIST REVERSE: definition + a counter + one failure.

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 — Neha uses it for a ticket queue node in a counter.
RuleLINKED LIST REVERSE → head → next → ….
RememberLINKED LIST REVERSE + a dry-run table (a counter).
UseLINKED LIST REVERSE in a counter (a ticket queue node).
TrapLINKED LIST REVERSE — losing the next pointer on delete.
ExLINKED LIST REVERSE → a ticket queue node.

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

Example

Short notes

Questions

LINKED LIST REVERSE

Example

Short notes

Questions