Let's now move to next important concept asked in coding interviews: Linked Lists:

Linked Lists test your ability to handle pointers, edge cases, and memory efficiency. They show up in both beginner and advanced interview rounds.

2.1. Reverse a Linked List

Example:
Reverse this list:
1 → 2 → 3 → 4
Output: 4 → 3 → 2 → 1

Concept tested:
Rewiring the .next pointers — often asked with follow-ups like iterative vs. recursive solutions.

2.2. Detect Cycle in a Linked List

Example:
In 1 → 2 → 3 → 4 → 2 (back to second node), detect the cycle.

Solution:
Use Floyd’s Cycle Detection Algorithm (fast and slow pointers).

It tests how well you manage infinite loops and pointer traversal without modifying the list.

2.3. Merge Two Sorted Linked Lists

Example:
Merge 1 → 3 → 5 and 2 → 4 → 6
Output: 1 → 2 → 3 → 4 → 5 → 6

Concept tested:
Efficient pointer traversal with dummy nodes or recursion. A classic sub-task in linked list sorting.

2.4. Find the Middle of a Linked List

Example:
In 1 → 2 → 3 → 4 → 5 → 6, the middle node is 4.

Solution:
Fast and slow pointer — when the fast pointer reaches the end, the slow one is at the middle.

2.5. Remove N-th Node from End

Example:
Remove the 2nd node from the end of 1 → 2 → 3 → 4 → 5
Output: 1 → 2 → 3 → 5

Trick:
Create a gap of n between two pointers and move them together — when the first hits the end, the second is at the right spot.

You’ll see linked lists hidden in many real-world structures — like undo-redo functionality, LRU cache, or browser history stacks.


React with ❤️ once you're ready for the next concept Hashing & Maps

Top 7 Coding Interview Concepts: https://whatsapp.com/channel/0029VammZijATRSlLxywEC3X/720

ENJOY LEARNING 👍👍