CS50 Fall 2025 - Lecture 5 - Data Structures (live, unedited) | CS50

In this lecture, the speaker discusses data structures in C programming, focusing on trade-offs between efficiency and memory usage. The lecture covers abstract data types like stacks and queues, illustrating their properties with real-world examples. It delves into the implementation of arrays, linked lists, binary search trees, and hash tables, explaining the advantages and disadvantages of each in terms of speed, memory allocation, and dynamic resizing. The lecture emphasizes the importance of choosing the right data structure based on specific problem requirements, highlighting the trade-offs between time and space complexity.

Outlines

Part 1: Abstract Data Types and Memory Basics

Part 2: Dynamic Memory Management

Part 3: Linked Lists

Part 4: Binary Search Trees

Part 5: Hashing and Hash Tables

Part 6: Tries and Real-World Applications

Sign in to continue reading, translating and more.

Open full episode in Podwise

CS50 Fall 2025 - Lecture 5 - Data Structures (live, unedited)

CS50

Part 1: Abstract Data Types and Memory Basics

Introduction to Data Structures: Stacks and Queues

Queues and Stacks: Abstract Data Types and Implementations

Dictionaries as Abstract Data Types and Array Limitations

Part 2: Dynamic Memory Management

Dynamic Memory Allocation with Malloc

Error Handling and Memory Management Best Practices

Realloc and Introduction to Structs

Part 3: Linked Lists

Linked Lists: Overcoming Array Limitations

Implementing a Linked List in C

Visualizing Linked List Construction in Memory

Traversing and Printing a Linked List

Analyzing the Running Time of Linked List Operations

Sorted Insertion and Code Walkthrough

Part 4: Binary Search Trees

Memory Management and Introduction to Trees

Binary Search Trees: A Two-Dimensional Approach

Searching and Implementing Binary Search Trees

Balanced vs. Unbalanced Trees

Part 5: Hashing and Hash Tables

Hashing: Mapping Infinite Domains to Finite Ranges

Hash Functions and Collisions

Hash Tables: Arrays of Linked Lists

Part 6: Tries and Real-World Applications

Tries: Achieving Constant Time Complexity

Trie Implementation and Real-World Examples

CS50 Fall 2025 - Lecture 5 - Data Structures (live, unedited)

CS50

Part 1: Abstract Data Types and Memory Basics

14:47Introduction to Data Structures: Stacks and Queues

Introduction to Data Structures: Stacks and Queues

18:03Queues and Stacks: Abstract Data Types and Implementations

Queues and Stacks: Abstract Data Types and Implementations

25:01Dictionaries as Abstract Data Types and Array Limitations

Dictionaries as Abstract Data Types and Array Limitations

Part 2: Dynamic Memory Management

30:11Dynamic Memory Allocation with Malloc

Dynamic Memory Allocation with Malloc

37:30Error Handling and Memory Management Best Practices

Error Handling and Memory Management Best Practices

44:28Realloc and Introduction to Structs

Realloc and Introduction to Structs

Part 3: Linked Lists

50:10Linked Lists: Overcoming Array Limitations

Linked Lists: Overcoming Array Limitations

55:12Implementing a Linked List in C

Implementing a Linked List in C

1:03:07Visualizing Linked List Construction in Memory

Visualizing Linked List Construction in Memory

1:11:01Traversing and Printing a Linked List

Traversing and Printing a Linked List

1:17:30Analyzing the Running Time of Linked List Operations

Analyzing the Running Time of Linked List Operations

1:20:30Sorted Insertion and Code Walkthrough

Sorted Insertion and Code Walkthrough

Part 4: Binary Search Trees

1:27:35Memory Management and Introduction to Trees

Memory Management and Introduction to Trees

1:36:02Binary Search Trees: A Two-Dimensional Approach

Binary Search Trees: A Two-Dimensional Approach

1:41:14Searching and Implementing Binary Search Trees

Searching and Implementing Binary Search Trees

1:47:45Balanced vs. Unbalanced Trees

Balanced vs. Unbalanced Trees

Part 5: Hashing and Hash Tables

1:53:04Hashing: Mapping Infinite Domains to Finite Ranges

Hashing: Mapping Infinite Domains to Finite Ranges

2:00:31Hash Functions and Collisions

Hash Functions and Collisions

2:07:06Hash Tables: Arrays of Linked Lists

Hash Tables: Arrays of Linked Lists

Part 6: Tries and Real-World Applications

2:15:15Tries: Achieving Constant Time Complexity

Tries: Achieving Constant Time Complexity

2:25:21Trie Implementation and Real-World Examples

Trie Implementation and Real-World Examples