Advent of Code 2025: Day 12 – checkerboard parity and knapsack DP for tetromino region fitting

Advent of Code 2025: Day 11 – DFS path counting with cycle detection and bitmask waypoints

Advent of Code 2025: Day 10 – meet-in-the-middle bitmasks and Gaussian elimination

Advent of Code 2025: Day 9 – finding the largest axis-aligned rectangle inside a polygon

Advent of Code 2025: Day 8 – clustering 3D boxes by Euclidean distance with Union-Find

Advent of Code 2025: Day 7 – BFS splits and memoized timeline counting on a stalk grid

Advent of Code 2025: Day 6 – applying column operators to number grids, with a cephalopod twist

Advent of Code 2025: Day 5 – counting and merging ID ranges for fresh ingredients

Advent of Code 2025: Day 4 – removing accessible paper rolls from a grid iteratively

Advent of Code 2025: Day 3 – extracting maximum joltage from digit sequences

Advent of Code 2025: Day 2 – finding IDs with repeating digit chunks in a range

Advent of Code 2025: Day 1 – navigating a 0–99 dial and counting zero crossings