difficulties.md

Difficulties

List of (relative) difficulties encountered while solving.

Please Note:

• The statistics on this page is not as refined as I would like it to be, will revisit problems, optimize them and update this page with refined and more accurate data.
• Instead of a single page, I am planning to add a per tag or per difficulty page for less overwhelming content.

xs

Day	Problem Page	Status	Difficulty	Solution Page	Test Page	Tags
2015/1	Not Quite Lisp	🥇	❄️	day_01.ex	day_01_test.exs	sequence, rust
2015/2	I Was Told There Would Be No Math	🥇	❄️	day_02.ex	day_02_test.exs	geometry2d, rust
2015/3	Perfectly Spherical Houses in a Vacuum	🥇	❄️	day_03.ex	day_03_test.exs	grid, set, rust
2015/5	Doesn't He Have Intern-Elves For This?	🥇	❄️	day_05.ex	day_05_test.exs	string
2015/10	Elves Look, Elves Say	🥇	❄️	day_10.ex	day_10_test.exs	string-encoding, sequence, reduction
2015/11	Corporate Policy	🥇	❄️	day_11.ex	day_11_test.exs	sequence, char-sequence, validation
2015/12	JSAbacusFramework.io	🥇	❄️	day_12.ex	day_12_test.exs	json
2016/2	Bathroom Security	🥇	❄️	day_02.ex	day_02_test.exs	grid, rust
2016/3	Squares With Three Sides	🥇	❄️	day_03.ex	day_03_test.exs	geometry2d, matrix, count
2016/4	Security Through Obscurity	🥇	❄️	day_04.ex	day_04_test.exs	sequence, checksum, rust
2016/6	Signals and Noise	🥇	❄️	day_06.ex	day_06_test.exs	sequence, optimization
2016/7	Internet Protocol Version 7	🥇	❄️	day_07.ex	day_07_test.exs	validation, count
2017/1	Inverse Captcha	🥇	❄️	day_01.ex	day_01_test.exs	sliding-window, rust
2017/2	Corruption Checksum	🥇	❄️	day_02.ex	day_02_test.exs	arithmetic, sequence, rust
2017/4	High-Entropy Passphrases	🥇	❄️	day_04.ex	day_04_test.exs	validation, rust
2019/1	The Tyranny of the Rocket Equation	🥇	❄️	day_01.ex	day_01_test.exs	calculation, rust
2019/2	1202 Program Alarm	🥇	❄️	day_02.ex	day_02_test.exs	op-code, not-fast-enough, int-code
2019/3	Crossed Wires	🥇	❄️	day_03.ex	day_03_test.exs	grid, set, not-fast-enough
2019/4	Secure Container	🥇	❄️	day_04.ex	day_04_test.exs	sequence, inline-input, not-fast-enough
2019/5	Sunny with a Chance of Asteroids	🥈	❄️	day_05.ex	day_05_test.exs	op-code, int-code
2019/6	Universal Orbit Map	🥇	❄️	day_06.ex	day_06_test.exs	graph, routing
2019/8	Space Image Format	🥇	❄️	day_08.ex	day_08_test.exs	sequence, visual-result
2021/1	Sonar Sweep	🥇	❄️	day_01.ex	day_01_test.exs	sliding-window, sequence, rust
2021/2	Dive!	🥇	❄️	day_02.ex	day_02_test.exs	grid, rust
2021/5	Hydrothermal Venture	🥇	❄️	day_05.ex	day_05_test.exs	set
2021/7	The Treachery of Whales	🥇	❄️	day_07.ex	day_07_test.exs	calculation
2022/1	Calorie Counting	🥇	❄️	day_01.ex	day_01_test.exs	sequence, rust
2022/2	Rock Paper Scissors	🥇	❄️	day_02.ex	day_02_test.exs	table-lookup
2022/3	Rucksack Reorganization	🥇	❄️	day_03.ex	day_03_test.exs	set
2022/4	Camp Cleanup	🥇	❄️	day_04.ex	day_04_test.exs	range, set
2022/6	Tuning Trouble	🥇	❄️	day_06.ex	day_06_test.exs	bitwise, set
2022/7	No Space Left On Device	🥇	❄️	day_07.ex	day_07_test.exs	op-code, linked-list
2023/1	Trebuchet?!	🥇	❄️	day_01.ex	day_01_test.exs	regex, rust
2023/4	Scratchcards	🥇	❄️	day_04.ex	day_04_test.exs	set, reduction
2023/6	Wait For It	🥇	❄️	day_06.ex	day_06_test.exs	algebra
2023/9	Mirage Maintenance	🥇	❄️	day_09.ex	day_09_test.exs	sequence, reduction
2024/1	Historian Hysteria	🥇	❄️	day_01.ex	day_01_test.exs	list
2024/3	Mull It Over	🥇	❄️	day_03.ex	day_03_test.exs	regex, fsm
2024/5	Print Queue	🥇	❄️	day_05.ex	day_05_test.exs	set, sort

s

Day	Problem Page	Status	Difficulty	Solution Page	Test Page	Tags
2015/4	The Ideal Stocking Stuffer	🥇	❄️ ❄️	day_04.ex	day_04_test.exs	md5, annoying
2015/9	All in a Single Night	🥇	❄️ ❄️	day_09.ex	day_09_test.exs	graph, routing
2015/13	Knights of the Dinner Table	🥇	❄️ ❄️	day_13.ex	day_13_test.exs	brute-force, combinatorics, slow
2015/14	Reindeer Olympics	🥇	❄️ ❄️	day_14.ex	day_14_test.exs	measurement, recursion, sequence
2015/17	No Such Thing as Too Much	🥇	❄️ ❄️	day_17.ex	day_17_test.exs	not-fast-enough, combinatorics
2016/1	No Time for a Taxicab	🥇	❄️ ❄️	day_01.ex	day_01_test.exs	grid, measurement, set, rust
2016/5	How About a Nice Game of Chess?	🥇	❄️ ❄️	day_05.ex	day_05_test.exs	slow, md5, annoying
2016/12	Leonardo's Monorail	🥇	❄️ ❄️	day_12.ex	day_12_test.exs	slow, op-code
2017/5	A Maze of Twisty Trampolines, All Alike	🥇	❄️ ❄️	day_05.ex	day_05_test.exs	not-fast-enough, random-access
2017/8	I Heard You Like Registers	🥇	❄️ ❄️	day_08.ex	day_08_test.exs	op-code
2017/9	Stream Processing	🥇	❄️ ❄️	day_09.ex	day_09_test.exs	fsm
2017/10	Knot Hash	🥇	❄️ ❄️	day_10.ex	day_10_test.exs	hash
2017/12	Digital Plumber	🥇	❄️ ❄️	day_12.ex	day_12_test.exs	disjoint-set
2017/13	Packet Scanners	🥇	❄️ ❄️	day_13.ex	day_13_test.exs	sequence, slow
2018/1	Chronal Calibration	🥇	❄️ ❄️	day_01.ex	day_01_test.exs	sequence, set, rust
2018/2	Inventory Management System	🥇	❄️ ❄️	day_02.ex	day_02_test.exs	checksum, string-result, set
2018/4	Repose Record	🥇	❄️ ❄️	day_04.ex	day_04_test.exs	date-time, sequence, sort, map
2018/6	Chronal Coordinates	🥇	❄️ ❄️	day_06.ex	day_06_test.exs	not-fast-enough, grid, measurement
2018/9	Marble Mania	🥇	❄️ ❄️	day_09.ex	day_09_test.exs	not-fast-enough, circular-linked-list
2021/3	Binary Diagnostic	🥇	❄️ ❄️	day_03.ex	day_03_test.exs	calculation
2021/4	Giant Squid	🥇	❄️ ❄️	day_04.ex	day_04_test.exs	grid, random-access, optimization
2021/6	Lanternfish	🥇	❄️ ❄️	day_06.ex	day_06_test.exs	map
2022/5	Supply Stacks	🥇	❄️ ❄️	day_05.ex	day_05_test.exs	parse-heavy, stack, linked-list
2022/13	Distress Signal	🥇	❄️ ❄️	day_13.ex	day_13_test.exs	json, sequence
2022/21	Monkey Math	🥇	❄️ ❄️	day_21.ex	day_21_test.exs	erlang, op-code, large-number, arithmetic
2023/2	Cube Conundrum	🥇	❄️ ❄️	day_02.ex	day_02_test.exs	reduction
2023/8	Haunted Wasteland	🥇	❄️ ❄️	day_08.ex	day_08_test.exs	arithmetic, sequence
2023/11	Cosmic Expansion	🥇	❄️ ❄️	day_11.ex	day_11_test.exs	grid, measurement
2023/15	Lens Library	🥇	❄️ ❄️	day_15.ex	day_15_test.exs	hash, ordered-map

m

Day	Problem Page	Status	Difficulty	Solution Page	Test Page	Tags
2015/6	Probably a Fire Hazard	🥇	❄️ ❄️ ❄️	day_06.ex	day_06_test.exs	grid, vector, reduction, slow
2015/7	Some Assembly Required	🥇	❄️ ❄️ ❄️	day_07.ex	day_07_test.exs	genserver, data-modelling, op-code
2015/8	Matchsticks	🥇	❄️ ❄️ ❄️	day_08.ex	day_08_test.exs	string-encoding, annoying
2015/15	Science for Hungry People	🥇	❄️ ❄️ ❄️	day_15.ex	day_15_test.exs	quadratic-time, not-fast-enough, sequence, needs-improvement
2015/16	Aunt Sue	🥇	❄️ ❄️ ❄️	day_16.ex	day_16_test.exs	hard-description, count
2015/18	Like a GIF For Your Yard	🥇	❄️ ❄️ ❄️	day_18.ex	day_18_test.exs	grid, map, not-fast-enough
2015/19	Medicine for Rudolph	🥇	❄️ ❄️ ❄️	day_19.ex	day_19_test.exs	not-fast-enough, needs-improvement, vector, random-access
2015/23	Opening the Turing Lock	🥇	❄️ ❄️ ❄️	day_23.ex	day_23_test.exs	op-code, emulation
2015/25	Let It Snow	🥇	❄️ ❄️ ❄️	day_25.ex	day_25_test.exs	table-lookup, modular-arithmetic
2016/8	Two-Factor Authentication	🥇	❄️ ❄️ ❄️	day_08.ex	day_08_test.exs	visual-result, matrix, op-code
2016/9	Explosives in Cyberspace	🥇	❄️ ❄️ ❄️	day_09.ex	day_09_test.exs	sequence, unfold
2016/10	Balance Bots	🥇	❄️ ❄️ ❄️	day_10.ex	day_10_test.exs	data-modelling, genserver
2017/3	Spiral Memory	🥇	❄️ ❄️ ❄️	day_03.ex	day_03_test.exs	spiral, matrix
2017/6	Memory Reallocation	🥇	❄️ ❄️ ❄️	day_06.ex	day_06_test.exs	sequence, reduction
2017/7	Recursive Circus	🥈	❄️ ❄️ ❄️	day_07.ex	day_07_test.exs	tree
2017/14	Disk Defragmentation	🥈	❄️ ❄️ ❄️	day_14.ex	day_14_test.exs	not-fast-enough, half-done, hash
2017/16	Permutation Promenade	🥇	❄️ ❄️ ❄️	day_16.ex	day_16_test.exs	op-code, count
2017/17	Spinlock	🥇	❄️ ❄️ ❄️	day_17.ex	day_17_test.exs	vector, random-access, not-fast-enough
2017/18	Duet	🥈	❄️ ❄️ ❄️	day_18.ex	day_18_test.exs	data-modelling, op-code, half-done
2017/23	Coprocessor Conflagration	🥈	❄️ ❄️ ❄️	day_23.ex	day_23_test.exs	op-code
2018/3	No Matter How You Slice It	🥇	❄️ ❄️ ❄️	day_03.ex	day_03_test.exs	grid, set, not-fast-enough
2019/10	Monitoring Station	🥇	❄️ ❄️ ❄️	day_10.ex	day_10_test.exs	sequence, grid, trigonometry
2021/9	Smoke Basin	🥇	❄️ ❄️ ❄️	day_09.ex	day_09_test.exs	graph, scc
2021/16	Packet Decoder	🥇	❄️ ❄️ ❄️	day_16.ex	day_16_test.exs	bitwise
2021/25	Sea Cucumber	🥇	❄️ ❄️ ❄️	day_25.ex	day_25_test.exs	vector, quadratic, not-fast-enough, grid
2022/8	Treetop Tree House	🥇	❄️ ❄️ ❄️	day_08.ex	day_08_test.exs	erlang, grid
2022/9	Rope Bridge	🥇	❄️ ❄️ ❄️	day_09.ex	day_09_test.exs	erlang, grid, walk
2022/10	Cathode-Ray Tube	🥇	❄️ ❄️ ❄️	day_10.ex	day_10_test.exs	erlang, visual-result, op-code
2022/12	Hill Climbing Algorithm	🥇	❄️ ❄️ ❄️	day_12.ex	day_12_test.exs	graph, graph-traversal, slow, needs-improvement
2022/20	Grove Positioning System	🥇	❄️ ❄️ ❄️	day_20.ex	day_20_test.exs	slow, vector, sequence, large-number, random-access
2022/23	Unstable Diffusion	🥇	❄️ ❄️ ❄️	day_23.ex	day_23_test.exs	erlang, slow, grid, walk
2022/24	Blizzard Basin	🥇	❄️ ❄️ ❄️	day_24.ex	day_24_test.exs	erlang, slow, optimization, grid, search
2022/25	Full of Hot Air	🥇	❄️ ❄️ ❄️	day_25.ex	day_25_test.exs	number-system
2023/3	Gear Ratios	🥇	❄️ ❄️ ❄️	day_03.ex	day_03_test.exs	grid
2023/7	Camel Cards	🥇	❄️ ❄️ ❄️	day_07.ex	day_07_test.exs	map, pattern-matching
2023/13	Point of Incidence	🥇	❄️ ❄️ ❄️	day_13.ex	day_13_test.exs	sliding-window, palindrome
2024/12	Garden Groups	🥈	❄️ ❄️ ❄️	day_12.ex	day_12_test.exs	geometry, disjoint-set

l

Day	Problem Page	Status	Difficulty	Solution Page	Test Page	Tags
2015/20	Infinite Elves and Infinite Houses	🥇	❄️ ❄️ ❄️ ❄️	day_20.ex	day_20_test.exs	slow, infinite-sequence, sequence
2015/21	RPG Simulator 20XX	🥇	❄️ ❄️ ❄️ ❄️	day_21.ex	day_21_test.exs	double-parse, data-modelling, combinatorics, strategy
2017/11	Hex Ed	🥇	❄️ ❄️ ❄️ ❄️	day_11.ex	day_11_test.exs	hexagon
2017/15	Dueling Generators	🥇	❄️ ❄️ ❄️ ❄️	day_15.ex	day_15_test.exs	number-theory, bitwise, slow
2018/5	Alchemical Reduction	🥇	❄️ ❄️ ❄️ ❄️	day_05.ex	day_05_test.exs	reduction
2018/8	Memory Maneuver	🥈	❄️ ❄️ ❄️ ❄️	day_08.ex	day_08_test.exs	sequence, walk
2021/15	Chiton	🥇	❄️ ❄️ ❄️ ❄️	day_15.ex	day_15_test.exs	graph, graph-route, slow
2022/11	Monkey in the Middle	🥇	❄️ ❄️ ❄️ ❄️	day_11.ex	day_11_test.exs	erlang, parse-heavy, arithmetic
2022/14	Regolith Reservoir	🥇	❄️ ❄️ ❄️ ❄️	day_14.ex	day_14_test.exs	live-book, visualized, slow, flood-fill, unfold
2023/14	Parabolic Reflector Dish	🥇	❄️ ❄️ ❄️ ❄️	day_14.ex	day_14_test.exs	grid, rotation, modular-arithmetic, memoization
2023/16	The Floor Will Be Lava	🥇	❄️ ❄️ ❄️ ❄️	day_16.ex	day_16_test.exs	grid, memoization
2023/18	Lavaduct Lagoon	🥇	❄️ ❄️ ❄️ ❄️	day_18.ex	day_18_test.exs	geometry
2023/19	Aplenty	🥇	❄️ ❄️ ❄️ ❄️	day_19.ex	day_19_test.exs	op-code, parse-heavy

xl

Day	Problem Page	Status	Difficulty	Solution Page	Test Page	Tags
2015/24	It Hangs in the Balance	🥇	❄️ ❄️ ❄️ ❄️ ❄️	day_24.ex	day_24_test.exs	not-fast-enough, power-set, ambiguous-solution
2021/21	Dirac Dice	🥇	❄️ ❄️ ❄️ ❄️ ❄️	day_21.ex	day_21_test.exs	slow, needs-improvement
2022/15	Beacon Exclusion Zone	🥇	❄️ ❄️ ❄️ ❄️ ❄️	day_15.ex	day_15_test.exs	erlang, slow, large-number, geometry2d
2022/18	Boiling Boulders	🥇	❄️ ❄️ ❄️ ❄️ ❄️	day_18.ex	day_18_test.exs	erlang, geometry3d, surface, set
2022/19	Not Enough Minerals	🥇	❄️ ❄️ ❄️ ❄️ ❄️	day_19.ex	day_19_test.exs	erlang, slow, needs-improvement, grid, optimization
2023/5	If You Give A Seed A Fertilizer	🥇	❄️ ❄️ ❄️ ❄️ ❄️	day_05.ex	day_05_test.exs	range, gb-tree
2023/10	Pipe Maze	🥇	❄️ ❄️ ❄️ ❄️ ❄️	day_10.ex	day_10_test.exs	graph, graph-traversal, needs-improvement, not-fast-enough
2023/12	Hot Springs	🥇	❄️ ❄️ ❄️ ❄️ ❄️	day_12.ex	day_12_test.exs	memoization, vector
2023/22	Sand Slabs	🥇	❄️ ❄️ ❄️ ❄️ ❄️	day_22.ex	day_22_test.exs	stack, range, not-fast-enough
2023/23	A Long Walk	🥇	❄️ ❄️ ❄️ ❄️ ❄️	day_23.ex	day_23_test.exs	graph, longest-path, slow, refactor
2023/25	Snowverload	🥇	❄️ ❄️ ❄️ ❄️ ❄️	day_25.ex	day_25_test.exs	graph, min-cut, probabilistic, refactor, not-fast-enough

xxl

Day	Problem Page	Status	Difficulty	Solution Page	Test Page	Tags
2022/22	Monkey Map	🥈	❄️ ❄️ ❄️ ❄️ ❄️ ❄️	day_22.ex	day_22_test.exs	half-done, geometry3d, walk3d
2023/24	Never Tell Me The Odds	🥇	❄️ ❄️ ❄️ ❄️ ❄️ ❄️	day_24.ex	day_24_test.exs	geometry2d, refactor

N/A

Day	Problem Page	Status	Difficulty	Solution Page	Test Page	Tags
2020/1	Report Repair	🥇	🤷	day_01.ex	day_01_test.exs
2020/2	Password Philosophy	🥇	🤷	day_02.ex	day_02_test.exs
2020/3	Toboggan Trajectory	🥇	🤷	day_03.ex	day_03_test.exs
2020/4	Passport Processing	🥇	🤷	day_04.ex	day_04_test.exs
2020/5	Binary Boarding	🥇	🤷	day_05.ex	day_05_test.exs
2020/6	Custom Customs	🥇	🤷	day_06.ex	day_06_test.exs
2020/7	Handy Haversacks	🥇	🤷	day_07.ex	day_07_test.exs
2020/8	Handheld Halting	🥇	🤷	day_08.ex	day_08_test.exs
2020/9	Encoding Error	🥇	🤷	day_09.ex	day_09_test.exs
2020/10	Adapter Array	🥇	🤷	day_10.ex	day_10_test.exs
2020/11	Seating System	🥇	🤷	day_11.ex	day_11_test.exs
2020/12	Rain Risk	🥇	🤷	day_12.ex	day_12_test.exs
2020/13	Shuttle Search	🥇	🤷	day_13.ex	day_13_test.exs
2020/14	Docking Data	🥇	🤷	day_14.ex	day_14_test.exs
2020/15	Rambunctious Recitation	🥇	🤷	day_15.ex	day_15_test.exs
2020/16	Ticket Translation	🥈	🤷	day_16.ex	day_16_test.exs
2020/18	Operation Order	🥇	🤷	day_18.ex	day_18_test.exs
2020/19	Monster Messages	🥇	🤷	day_19.ex	day_19_test.exs
2020/20	Jurassic Jigsaw	🥈	🤷	day_20.ex	day_20_test.exs
2020/21	Allergen Assessment	🥇	🤷	day_21.ex	day_21_test.exs
2020/22	Crab Combat	🥇	🤷	day_22.ex	day_22_test.exs
2020/23	Crab Cups	🥇	🤷	day_23.ex	day_23_test.exs
2020/24	Lobby Layout	🥈	🤷	day_24.ex	day_24_test.exs
2020/25	Combo Breaker	🥇	🤷	day_25.ex	day_25_test.exs