Data Structure and Algorithm II

Master Key Data Structures: Linked Lists, Queues, Stacks and Hash Table through curated LeetCode problem solving.

Linked List

Stack

Queue

Hash Table

Duration

4 weeks

Introduction

Welcome to Data Structures and Algorithms II, where you’ll build a rock-solid foundation in four essential data structures: Linked Lists, Queues, Stacks, and Hash Tables. This course is designed to transform abstract concepts into practical problem-solving skills through curated LeetCode problems that mirror real-world coding interviews.

Prerequisites

Complete Data Structure and Algorithm I Unit.

Skills Covered

In this unit, we are going to cover the following topics.

Linked Lists: Traversal, reversal, merging, and cycle detection.

Queues & Stacks: Implementations, applications, and classic problems.

Hash Tables: Efficient lookups, collision handling, and real-world use cases.

Recommended Study Material

Linked list

This video explains the linked list data structure and its implementation.

Linked List

Data Structure

Duration:

1 hour

Stacks and Queues

This video explains the Stack and Queue data structure and its implementation.

Stack

Queue

Data Structure

Duration:

1 hour

Hash Tables

This video explains the Hash Table data structure and its implementation.

Hash Table

Data Structure

Duration:

1 hour

Practice Problems

Status	Bookmark	Problem	Difficulty	Tags	Solution
		Reverse Linked List	Easy
		Linked List Cycle	Easy
		Intersection of Two Linked Lists	Easy
		Merge Two Sorted Lists	Easy
		Remove Duplicates from Sorted List	Easy
		Middle of the Linked List	Easy
		Linked List Cycle II	Medium
		Reverse Linked List II	Medium
		Design Linked List	Medium
		Insertion Sort List	Medium
		Remove Duplicates from Sorted List II	Medium
		Remove Nth Node From End of List	Medium
		Copy List with Random Pointer	Medium
		Add Two Numbers	Medium
		Flatten a Multilevel Doubly Linked List	Medium
		Design Browser History	Medium
		Merge k Sorted Lists	Hard
		Reverse Nodes in k-Group	Hard
		Baseball Game	Easy
		Valid Parentheses	Easy
		Implement Queue using Stacks	Easy
		Remove All Adjacent Duplicates In String	Easy
		Min Stack	Medium
		Evaluate Reverse Polish Notation	Medium
		Generate Parentheses	Medium
		Asteroid Collision	Medium
		132 Pattern	Medium
		Daily Temperatures	Medium
		Simplify Path	Medium
		Online Stock Span	Medium
		Car Fleet	Medium
		Basic Calculator	Medium
		Basic Calculator II	Medium
		Maximum Frequency Stack	Hard
		Longest Valid Parentheses	Hard
		Largest Rectangle in Histogram	Hard
		Number of Visible People in a Queue	Hard
		Number of Students Unable to Eat Lunch	Easy
		Implement Stack using Queues	Easy
		Number of Recent Calls	Easy
		Time Needed to Buy Tickets	Easy
		Design Circular Queue	Medium
		Design Circular Deque	Medium
		Reveal Cards In Increasing Order	Medium
		Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit	Medium
		Design Circular Queue	Medium
		Jump Game VI	Medium
		Sliding Window Maximum	Hard
		Max Value of Equation	Hard
		Contains Duplicate	Easy
		Valid Anagram	Easy
		Merge Similar Items	Easy
		Two Sum	Easy
		Verifying an Alien Dictionary	Easy
		Design HashSet	Medium
		Longest Consecutive Sequence	Medium
		Design HashMap	Medium
		3Sum	Medium
		4Sum	Medium
		Group Anagrams	Medium
		Implement Router*	Medium
		Set Matrix Zeroes	Medium
		Longest Consecutive Sequence	Medium
		Time Based Key-Value Store	Medium
		Encode and Decode TinyURL	Medium
		Number of Good Ways to Split a String	Medium
		Number of Matching Subsequences	Medium
		Time Based Key-Value Store	Medium
		Snapshot Array	Medium
		Insert Delete GetRandom O(1)	Medium
		LRU Cache	Medium
		LFU Cache	Hard

Credit

The problem set is carefully curated from Neetcode and AlgoMaster, supplemented with additional practice questions for comprehensive coverage.

Contributor(s)

John Doe

Founder and Fullstack Developer at freeCodeProject.org

Created this Unit with curated list of questions for practice.