Ep720 Wolfram Language, Advent of Code 2025, Day 1

Video Summary (Generated by AI, Edited by Human.)

This video, "Ep720 Wolfram Language, Advent of Code 2025, Day 1," features Xah Lee attempting to solve Day 1 of the Advent of Code 2025 puzzle using Wolfram Language (0:09).

Key points of the video include:

Introduction to Wolfram Language: Xah Lee introduces the Wolfram Language as a highly advanced programming language and mentions his extensive tutorials and resources for it (1:34-2:08). He also touches upon using Emacs with Wolfram Mode for coding (2:15-2:27).

Advent of Code Problem Description: The puzzle involves a safe with a dial numbered 0-99. The dial starts at 50, and a sequence of left (L) or right (R) rotations is provided. The challenge is to find the "password," which is the number of times the dial points to zero after any rotation in the sequence (3:08-14:16). A significant portion of the video is spent clarifying the ambiguous phrasing of the problem statement, particularly the term "left pointing at zero" (14:46-19:21).

Problem-Solving Approach:

The numbers 0-99 are arranged in a circle, meaning modular arithmetic (modulo 100) is crucial for calculations (5:53-13:04).

Left rotations are treated as subtraction, and right rotations as addition (9:33-13:04).

The video also discusses extracting the direction (L/R) and the rotation distance from the input strings (37:51-49:23).

Coding in Wolfram Language: Xah Lee demonstrates how to implement the solution using Wolfram Language's features, including StringStartQ for checking the rotation direction and ToExpression for converting the rotation distance from a string to a number (43:08-49:23). He then attempts to use the FoldList function to track the dial's position after each rotation (53:48-53:52, 1:11:27-1:11:31).

Notes at
http://xahlee.info/talk_show/xah_talk...
If browser says security error, that is because it auto changes URL from HTTP to HTTPS.
It's a way to censor 22 million old websites.
Remove the S in HTTPS.
Or use brave browser or safari.