Problems

Note that you can solve most task in any order!
Already solved ones are at the bottom of the table.

Volume:

Simple Implementation Popular Algos Puzzles Special

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Id	Title	Translations	Author	Solved	Blessing
1	Sum "A+B"	DE ES FR AR ZH RO RU SK		53777	1.00
2	Sum in Loop	DE ES FR AR ZH RO RU SK		33034	1.85
3	Sums in Loop	DE ES FR AR ZH RO RU SK		25167	2.32
4	Minimum of Two	DE ES FR AR ZH RO RU SK		21911	2.56
5	Minimum of Three	DE ES FR AR ZH RO RU SK		19635	2.75
15	Maximum of array	DE ES AR ZH RO RU SK		17167	2.98
6	Rounding	DE ES AR ZH RO RU SK		15878	3.12
7	Fahrenheit to Celsius	DE ES AR ZH RO RU SK		15159	3.20
20	Vowel Count	DE ES AR ZH RO RU SK		12311	3.56
11	Sum of digits	DE ES RU ZH SK		12170	3.58
41	Median of Three	DE ES AR ZH RO RU SK		10525	3.83
8	Arithmetic Progression	DE ES RU ZH SK		11383	3.70
28	Body Mass Index	DE ES ZH RU SK		10366	3.86
9	Triangles	DE ES RU ZH SK		10812	3.79
13	Weighted sum of digits	DE ES RU ZH SK		9866	3.95
43	Dice Rolling	DE ES ZH RU SK		8932	4.12
16	Average of an array	DE ES RU SK		9350	4.04
30	Reverse String	DE RU SK		8808	4.14
17	Array Checksum	DE ES RU SK		8657	4.17
21	Array Counters	DE ES RU SK		8094	4.29
48	Collatz Sequence	DE ES RU SK		7037	4.53
10	Linear Function	DE ES RU SK		7759	4.36
12	Modulo and time difference	DE ES RU SK		7143	4.51
14	Modular Calculator	ES SK		6595	4.65
27	Bubble Sort	ES RU SK		5982	4.81
26	Greatest Common Divisor	RU SK		5835	4.86
18	Square Root	ES RU		5584	4.93
29	Sort with Indexes	RU		5398	4.99
50	Palindromes	DE ES RU SK		4936	5.15
23	Bubble in Array	ES RU		5175	5.07
52	Pythagorean Theorem	RU		4731	5.22
31	Rotate String	ES RU		4940	5.15
67	Fibonacci Sequence	RU		4292	5.39
68	Bicycle Race	ES RU		4260	5.40
57	Smoothing the Weather	ES RU		4296	5.39
24	Neumann's Random Generator	DE ES RU		4616	5.26
104	Triangle Area			3364	5.81
35	Savings Calculator			4045	5.49
25	Linear Congruential Generator	RU		4005	5.51
81	Bit Count	RU		3415	5.79
44	Double Dice Roll	RU		3793	5.61
32	Josephus Problem	RU		3895	5.56
128	Combinations Counting			2672	6.21
19	Matching Brackets	ES RU		3631	5.68
58	Card Names			3241	5.88
47	Caesar Shift Cipher	SK		3327	5.83
49	Rock Paper Scissors			3273	5.86
55	Matching Words			3182	5.91
94	Fool's Day 2014	SK		2770	6.15
59	Bulls and Cows			2863	6.09
61	Prime Numbers Generation	RU		2819	6.12
22	Two Printers	ES RU		3017	6.00
42	Blackjack Counting			2591	6.27
120	Selection Sort			2035	6.69
406	Wormholes of Cygnus		moxieman	6	16.54
38	Quadratic Equation			2387	6.41
33	Parity Control	RU		2339	6.45
171	Tree Height Measurement			1448	7.28
53	King and Queen			2093	6.64
34	Binary Search			2154	6.59
69	Fibonacci Divisibility			1854	6.85
37	Mortgage Calculator	ZH		2021	6.70
45	Cards Shuffling	ZH		1965	6.75
63	Integer Factorization	ZH		1778	6.92
46	Tic-Tac-Toe	ZH		1823	6.88
72	Funny Words Generator			1590	7.12
62	Prime Ranges			1626	7.08
121	Insertion Sort			1344	7.41
172	Cloud Altitude Measurement			1083	7.78
127	Anagrams			1271	7.50
75	Yacht or Dice Poker			1503	7.21
134	Flying Text Screensaver			1175	7.64
39	Share Price Volatility			1504	7.21
405	Three Friendly Knights		csfpython	7	16.31
156	Luhn Algorithm	SK		995	7.93
114	Tricky Printing			1118	7.73
80	Duel Chances			1133	7.70
135	Variable Length Code			888	8.13
74	Clock Hands			1068	7.81
36	Code Guesser	UA		1165	7.66
105	Convex Polygon Area			915	8.07
54	Pythagorean Triples			1034	7.86
145	Modular Exponentiation			767	8.38
73	Hexagonal Grid			944	8.02
116	Summing Up			810	8.29
399	Methane Identification		moxieman	21	14.55
385	Number of steps in Euclidean Algorithm		gardengnome	59	12.81
97	Girls and Pigs			844	8.21
187	Static Web Page			583	8.86
181	Reverse Polish Notation			583	8.86
188	Basics of HTML			557	8.94
401	Methane Rotation		moxieman	14	15.22
122	QuickSort			680	8.59
98	Azimuth at Treasure Island			729	8.47
400	Memory Check			15	15.11
85	Rotation in 2D Space			734	8.46
51	Dungeons and Dragons Dice	UA		794	8.32
377	Sum of Digits Divisibility			65	12.64
56	Life is Simple			768	8.38
70	Most Frequent Word			705	8.53
40	Paths in the Grid	UA		764	8.39
66	Caesar Cipher Cracker			706	8.52
88	Pitch and Notes			645	8.68
108	Star Medals			595	8.82
211	Information Entropy			365	9.67
95	Simple Linear Regression			581	8.86
87	Tree Builder			590	8.84
207	Suffix Array			364	9.67
60	Sweet Harvest			622	8.74
77	Point to Segment Distance			585	8.85
403	Hi-Lo dice game			6	16.54
176	Say 100			399	9.51
86	Brainfuck Interpreter			550	8.96
404	Methane Normalization		moxieman	4	17.13
143	Extended Euclidean Algorithm			434	9.37
195	Mul Two			346	9.76
71	Fibonacci Divisibility Advanced			546	8.97
91	Game of 2048			509	9.09
191	Spaceship Weight Fraud			342	9.78
119	Brain Fibo			454	9.29
101	Gradient Calculation			476	9.21
206	Base-32 Encoding			309	9.96
82	Levenshtein Distance			488	9.17
89	Instrument Tuner			455	9.29
131	Four Pics One Word			386	9.57
64	Maze Pathfinder			473	9.22
189	Dynamic Web Page			300	10.01
79	Cycles Detection			436	9.36
92	Binary Heap			413	9.45
150	Introducing Regexps			328	9.85
366	Image Cutting		oezguery	51	13.06
126	Sequence of Squares			354	9.72
136	Variable Length Code Unpack			341	9.79
170	Binary Search in Array			290	10.07
167	Copy Line			292	10.05
197	Loops in Assembly			255	10.29
83	Graph Generator			391	9.55
90	Lexicographic Permutations			376	9.62
301	Skyscraper Price			125	11.52
154	Breadth First Search			294	10.04
78	Bezier Curves			378	9.61
117	Divide by Two			321	9.89
99	Uphill Shooting			333	9.83
65	Transitive Closure on Candy States			362	9.68
374	Longest Common Subsequence			34	13.75
144	Modular Inverse			272	10.18
371	Pages to Print			36	13.65
155	Depth First Search			258	10.27
174	Calculation of Pi			235	10.43
402	Game of Stones		csfpython	4	17.13
161	Topological Sorting			242	10.38
384	Equal Hamming Distance		csfpython	21	14.55
133	Billiard Ball			260	10.26
165	Safe Landing			229	10.48
190	Query String Parameters			202	10.69
140	Proper Bracket Sequences			243	10.37
184	Matches Picking		quandray	200	10.71
323	Next Palindrome		csfpython	74	12.42
76	Pawn Move Validator			291	10.06
96	Snake Arcade			271	10.18
360	Whisky Blending		csfpython	39	13.51
103	Easter Eggs			257	10.28
381	Finding Squares		csfpython	21	14.55
123	Knapsack of Integers			238	10.41
93	Starving Priority Queue			262	10.24
130	Combinations with Repetitions			228	10.48
173	Chords of Music			192	10.78
84	Dijkstra in the Network			265	10.22
368	Number Base Palindrome		csfpython	31	13.90
125	Bogosort			230	10.47
337	Introducing Zeckendorf		csfpython	55	12.93
389	Binary Split Guessing Game		csfpython	13	15.34
372	String Minimization			26	14.20
390	Card Pairing Solitaire			12	15.47
146	Color Cubes			198	10.73
109	Lucky Tickets			226	10.50
151	Word Ladders			190	10.80
208	Neighborhood of a String			144	11.28
393	Urban Planning		csfpython	9	15.92
164	Page Rank			172	10.97
129	Enumerating Combinations			196	10.74
364	Arthur Engel's Randomizer			29	14.01
194	Convex Hull and Farmers			147	11.24
329	Roman Arithmetic		csfpython	53	12.99
138	Huffman Coding			185	10.84
139	Beam Balance and Masses			182	10.87
201	Point in Polygon			138	11.35
199	Employees Web App			139	11.34
359	Find 3 Numbers		csfpython	31	13.90
398	Collecting Diamonds		csfpython	5	16.81
192	Gangster Battles			136	11.38
152	RSA Cryptography			161	11.08
388	Fibonacci Guessing Game			11	15.61
137	Shannon-Fano Coding			168	11.01
111	Necklace Count			176	10.93
244	Introducing SQL			95	11.99
110	Lucky Tickets Advanced			166	11.03
168	Caesar meets BF			133	11.41
245	Aggregations in SQL			86	12.16
269	Fibonacci coding			73	12.45
392	Fixing an Anagram			7	16.31
202	Dancing Pairs			108	11.77
179	Look and Say binary			119	11.61
198	Prn Hex Str			109	11.76
386	Advent Calendar Chocolate		gardengnome	10	15.76
162	Rubik's Cube			126	11.51
148	Public Key Cryptography Intro			133	11.41
214	Sick Travellers			98	11.94
182	Frodo and Black Riders			112	11.71
124	Knapsack Backtracking			141	11.31
395	Growth of Micro-Organisms		csfpython	5	16.81
106	Random Search Optimization			149	11.22
177	Nim Game			112	11.71
253	Beautiful Line Chart			74	12.42
185	Simple 3D Scene			106	11.80
160	Social Web Scraper			117	11.63
294	Vigenere Cipher			52	13.03
102	Travelling Salesman			139	11.34
157	Emirp primE			113	11.69
158	Hamming Codes			111	11.73
258	Text Justification			65	12.64
246	Joins in SQL			70	12.52
379	Dice with Infinity Sides		telebashna	11	15.61
291	Squirrels vs. Acorns		zelevin	48	13.16
159	Hard Life			103	11.85
281	Basic Tokenizer			51	13.06
265	Update in SQL			57	12.87
277	The Adventure of Morse Code		zelevin	52	13.03
196	Fibonacci Randomizer			85	12.18
397	Trading Bot			3	17.51
153	Fermat goes hacking RSA			99	11.92
351	Nicomachus			21	14.55
376	Cartesian Tree Visualization			11	15.61
394	Many Shortest Routes		csfpython	4	17.13
115	Gradient Descent for SLE			109	11.76
186	Simple 3D Scene (cont)			82	12.25
383	E2C2S - try harder!		gardengnome	8	16.11
335	Venus Visible			26	14.20
100	Crossing the Road			114	11.68
141	Sliding Window Search			97	11.96
210	Ticket Puzzle			69	12.54
209	Suffix Array Advanced			69	12.54
166	Page Rank as Eigenvector			83	12.23
375	Space Invaders			10	15.76
193	Maximum Flow			72	12.47
142	LZ77 decompression			89	12.11
203	Tic-Tac-Toe Minimax Algorithm			68	12.57
219	Neural Network Calculation			61	12.75
382	Die Throw Sequences		csfpython	7	16.31
363	Language Detector			13	15.34
112	Travelling Salesman Inverted			92	12.05
216	Cracking Linear Congruential Generator			59	12.81
352	Hurkle			16	15.00
274	Two Buckets			40	13.47
113	Ground Zero			89	12.11
315	Count the Common Factors		csfpython	27	14.13
334	Find all of the SETs		csfpython	21	14.55
387	Big Numbers		csfpython	5	16.81
132	Stream Cipher Breaking			80	12.29
163	Colliding Balls			70	12.52
259	Easter Bunnies		gardengnome	42	13.39
175	Algae Robot			66	12.62
354	Too Many Divisors		csfpython	14	15.22
205	Clustering the Stars			56	12.90
293	Sums of Triplets			31	13.90
200	Fizz Buzz in Asm			57	12.87
353	Hurkle Hunter			14	15.22
107	Knight's Tour			81	12.27
396	Chocolate Triangles and BF		moxieman	2	18.01
230	Move-To-Front Transform			47	13.20
347	Unwanted Multiples		csfpython	15	15.11
204	Wandering Star			53	12.99
212	BCD to Hex			50	13.09
292	Factorial Trailing Zeroes			29	14.01
330	Easter Bunnies Are Back		gardengnome	19	14.72
241	Village Ways			42	13.39
391	Scout Proficiency Badges		csfpython	3	17.51
367	Roguelike 1d			9	15.92
257	Missing Records in SQL			36	13.65
346	Long Decimal Fractions		csfpython	14	15.22
358	Mandelbrot Set			11	15.61
218	Rain Must Fall	DE		45	13.27
378	Space Invaders Automation			6	16.54
307	The Problem of Too Many Clues		zelevin	23	14.40
149	Prime Chains			60	12.78
338	Throwing Easter Eggs		gardengnome	15	15.11
233	Language Study			39	13.51
349	Burrows		gardengnome	12	15.47
380	Treap Study			5	16.81
362	Euclid, Manhattan and Chebyshev			9	15.92
357	Ulam's Prime Spiral			10	15.76
178	Maze of the Wumpus			49	13.13
361	Rogue Mazes			9	15.92
324	Merge Sort			17	14.90
147	Color Cubes Advanced			55	12.93
331	Rotating Toy Display		csfpython	15	15.11
118	Maxit Single-Player			59	12.81
180	Simple Game of Sticks			46	13.23
223	Introducing Scheme			37	13.60
297	Collatz in the Range			21	14.55
299	Tree Visualizer			20	14.63
340	Zeckendorf Lite		csfpython	12	15.47
287	Palindrome Frog		csfpython	22	14.48
339	Parking Lot			12	15.47
229	Burrows-Wheeler Transform			33	13.80
255	LCM of a range			28	14.07
296	Tree Value	RU	csfpython	20	14.63
183	Connect Four			41	13.43
247	Towers of Hanoi			29	14.01
313	Seven Segment Decoder			16	15.00
312	The Shredder Conundrum		zelevin	16	15.00
344	Throwing Easter Eggs Part 2		gardengnome	10	15.76
298	Revoltle		zelevin	18	14.81
270	Hexlife			22	14.48
341	Zeckendorf Advanced		csfpython	10	15.76
261	Easter Bunnies 2D		gardengnome	23	14.40
284	Rotate Array In-Place			19	14.72
290	Every Leaf on Every Tree		zelevin	18	14.81
282	Predictable Board Game		csfpython	19	14.72
332	Easter Bunnies 2D Are Back		gardengnome	11	15.61
249	Turing Increment			24	14.33
217	Personality Swap			29	14.01
286	Self-Printing Program			18	14.81
238	Bear Hunt			25	14.26
234	Train Merge			25	14.26
326	Sum Them Forth			11	15.61
275	Three Buckets			18	14.81
268	Logic Transformation			19	14.72
169	Automated Landing			33	13.80
343	Village of Ticks			8	16.11
350	Colourful Egg Sequences		gardengnome	7	16.31
300	Run-Length Encoding			14	15.22
314	The Sorites Solution		zelevin	12	15.47
285	Rotate Matrix In Place			16	15.00
243	Grille Encryption			21	14.55
256	Rook Jump Maze			19	14.72
271	A Knight some Trolls and a Princess		csfpython	17	14.90
369	Flappy Bird			4	17.13
345	Elliptic Curves Basics			7	16.31
213	Micro-Life	SK		24	14.33
306	Line Drawing Algorithm			12	15.47
250	Turing Clone			19	14.72
336	Currency Arbitrage			8	16.11
333	Happy Triplets			8	16.11
365	Flower Border Arrangements		csfpython	4	17.13
289	The Case of the Desperate Mastermind		zelevin	13	15.34
373	Railroad Rat		csfpython	3	17.51
220	Neural Network Training			21	14.55
260	Low Cost Road Network		csfpython	16	15.00
303	Towers Under Cover			11	15.61
311	The Mirror Maze		zelevin	10	15.76
309	Board Game Sequences		csfpython	10	15.76
263	Easter Bunnies 3D		gardengnome	15	15.11
262	Easter Bunnies 2D Advanced		gardengnome	15	15.11
316	Apogee			9	15.92
288	Langton's Ant		csfpython	12	15.47
370	Jewels			3	17.51
276	Lucky Pairs		csfpython	13	15.34
266	Pancake Sorting			14	15.22
320	Accordion		pearlbarley	8	16.11
231	Dice Black Jack			17	14.90
319	Tower of Hanoi Rules		csfpython	8	16.11
279	Two Buckets Advanced		csfpython	12	15.47
328	Beep Beep Beep			7	16.31
254	Rule 30 by Turing			14	15.22
305	The Catacombs of Chronos		zelevin	9	15.92
325	Ultimate Sort Trial			7	16.31
221	XWords		quandray	17	14.90
355	Robots Game			4	17.13
322	Gray Decoder			7	16.31
310	Board Game Sequences Advanced		csfpython	8	16.11
342	Adaptive Arithmetic Coding			5	16.81
222	Easter Eggs Advanced			16	15.00
308	Circle Drawing Algorithm			8	16.11
295	Vigenere Cipher Cracker			9	15.92
304	Ordered Brackets		csfpython	8	16.11
235	Train Merge Advanced			14	15.22
242	Comment Stripper			13	15.34
356	Robots Game Autoplay			3	17.51
327	Dobbin's Long Journey		csfpython	5	16.81
215	Klotski	SK		13	15.34
267	Turing Maze			9	15.92
237	Road Network Destruction			11	15.61
264	Party Presents		csfpython	9	15.92
302	Sound-Controlled Robot			6	16.54
227	Hashtable Implementation			11	15.61
226	Multiplicative Persistence Backtrace			11	15.61
225	Hamurabi			11	15.61
283	Predictable Board Game on 10 Boards		csfpython	7	16.31
248	Christmas Puzzle			9	15.92
278	Polyomino Generation			7	16.31
224	Transposing List of Lists			10	15.76
252	Shadok and Gibis			8	16.11
317	Launch to Orbit			4	17.13
236	Is the Earth Flat			8	16.11
273	Logic Glitches			6	16.54
251	Radio Spies			7	16.31
348	Trick-Taking Game			2	18.01
321	Hanoi Tower Heights		csfpython	3	17.51
232	Shift Register Randomizer			7	16.31
272	Hexplore			5	16.81
240	Playfair Cipher Cracking			6	16.54
239	Foxes and Geese			6	16.54
280	Three Buckets Re-visited		csfpython	4	17.13
318	Launch to Orbit automated			2	18.01
228	Maze Mapping Robot			5	16.81