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		53809	1.00
2	Sum in Loop	DE ES FR AR ZH RO RU SK		33043	1.85
3	Sums in Loop	DE ES FR AR ZH RO RU SK		25174	2.32
4	Minimum of Two	DE ES FR AR ZH RO RU SK		21920	2.56
5	Minimum of Three	DE ES FR AR ZH RO RU SK		19644	2.75
15	Maximum of array	DE ES AR ZH RO RU SK		17178	2.98
6	Rounding	DE ES AR ZH RO RU SK		15885	3.12
7	Fahrenheit to Celsius	DE ES AR ZH RO RU SK		15167	3.20
20	Vowel Count	DE ES AR ZH RO RU SK		12319	3.56
11	Sum of digits	DE ES RU ZH SK		12177	3.58
41	Median of Three	DE ES AR ZH RO RU SK		10531	3.83
8	Arithmetic Progression	DE ES RU ZH SK		11390	3.70
28	Body Mass Index	DE ES ZH RU SK		10372	3.86
9	Triangles	DE ES RU ZH SK		10815	3.79
13	Weighted sum of digits	DE ES RU ZH SK		9871	3.95
43	Dice Rolling	DE ES ZH RU SK		8937	4.12
16	Average of an array	DE ES RU SK		9356	4.04
30	Reverse String	DE RU SK		8814	4.14
17	Array Checksum	DE ES RU SK		8662	4.17
21	Array Counters	DE ES RU SK		8097	4.29
48	Collatz Sequence	DE ES RU SK		7042	4.53
10	Linear Function	DE ES RU SK		7764	4.36
12	Modulo and time difference	DE ES RU SK		7149	4.51
14	Modular Calculator	ES SK		6601	4.64
27	Bubble Sort	ES RU SK		5982	4.82
26	Greatest Common Divisor	RU SK		5837	4.86
18	Square Root	ES RU		5588	4.93
29	Sort with Indexes	RU		5401	4.99
50	Palindromes	DE ES RU SK		4938	5.15
23	Bubble in Array	ES RU		5177	5.07
52	Pythagorean Theorem	RU		4732	5.22
31	Rotate String	ES RU		4941	5.15
67	Fibonacci Sequence	RU		4293	5.39
68	Bicycle Race	ES RU		4262	5.40
57	Smoothing the Weather	ES RU		4297	5.39
24	Neumann's Random Generator	DE ES RU		4618	5.27
104	Triangle Area			3366	5.81
35	Savings Calculator			4048	5.49
25	Linear Congruential Generator	RU		4006	5.51
81	Bit Count	RU		3416	5.79
44	Double Dice Roll	RU		3795	5.61
32	Josephus Problem	RU		3897	5.56
128	Combinations Counting			2673	6.21
19	Matching Brackets	ES RU		3635	5.68
58	Card Names			3243	5.88
47	Caesar Shift Cipher	SK		3328	5.83
49	Rock Paper Scissors			3274	5.86
55	Matching Words			3183	5.91
94	Fool's Day 2014	SK		2771	6.15
59	Bulls and Cows			2864	6.09
61	Prime Numbers Generation	RU		2820	6.12
22	Two Printers	ES RU		3019	6.00
42	Blackjack Counting			2592	6.27
120	Selection Sort			2035	6.69
38	Quadratic Equation			2389	6.41
33	Parity Control	RU		2341	6.45
171	Tree Height Measurement			1450	7.28
53	King and Queen			2094	6.64
34	Binary Search			2155	6.59
69	Fibonacci Divisibility			1857	6.85
37	Mortgage Calculator	ZH		2022	6.70
45	Cards Shuffling	ZH		1965	6.75
63	Integer Factorization	ZH		1781	6.92
46	Tic-Tac-Toe	ZH		1826	6.88
72	Funny Words Generator			1592	7.11
62	Prime Ranges			1627	7.08
121	Insertion Sort			1345	7.41
172	Cloud Altitude Measurement			1084	7.78
127	Anagrams			1272	7.50
75	Yacht or Dice Poker			1505	7.21
134	Flying Text Screensaver			1178	7.64
39	Share Price Volatility			1505	7.21
156	Luhn Algorithm	SK		996	7.93
114	Tricky Printing			1120	7.73
407	River Labyrinth			6	16.54
80	Duel Chances			1134	7.70
135	Variable Length Code			889	8.13
74	Clock Hands			1070	7.80
36	Code Guesser	UA		1165	7.66
105	Convex Polygon Area			917	8.07
54	Pythagorean Triples			1036	7.86
145	Modular Exponentiation			767	8.38
73	Hexagonal Grid			945	8.02
116	Summing Up			813	8.28
97	Girls and Pigs			846	8.21
187	Static Web Page			583	8.86
181	Reverse Polish Notation			584	8.85
188	Basics of HTML			557	8.94
385	Number of steps in Euclidean Algorithm		gardengnome	59	12.81
122	QuickSort			680	8.59
98	Azimuth at Treasure Island			730	8.47
406	Wormholes of Cygnus		moxieman	6	16.54
85	Rotation in 2D Space			735	8.46
51	Dungeons and Dragons Dice	UA		795	8.32
399	Methane Identification		moxieman	21	14.55
56	Life is Simple			769	8.38
377	Sum of Digits Divisibility			66	12.62
70	Most Frequent Word			705	8.53
40	Paths in the Grid	UA		766	8.38
66	Caesar Cipher Cracker			706	8.53
88	Pitch and Notes			646	8.68
405	Three Friendly Knights		csfpython	7	16.31
401	Methane Rotation		moxieman	15	15.11
108	Star Medals			595	8.82
211	Information Entropy			366	9.66
95	Simple Linear Regression			581	8.86
87	Tree Builder			591	8.83
207	Suffix Array			364	9.67
60	Sweet Harvest			625	8.74
400	Memory Check			15	15.11
77	Point to Segment Distance			585	8.85
176	Say 100			399	9.52
86	Brainfuck Interpreter			551	8.96
143	Extended Euclidean Algorithm			435	9.37
195	Mul Two			346	9.76
71	Fibonacci Divisibility Advanced			546	8.97
91	Game of 2048			510	9.09
191	Spaceship Weight Fraud			342	9.78
119	Brain Fibo			455	9.29
101	Gradient Calculation			476	9.21
206	Base-32 Encoding			309	9.96
82	Levenshtein Distance			488	9.17
89	Instrument Tuner			456	9.28
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	9.46
150	Introducing Regexps			328	9.85
126	Sequence of Squares			354	9.72
136	Variable Length Code Unpack			341	9.79
170	Binary Search in Array			291	10.06
167	Copy Line			292	10.06
366	Image Cutting		oezguery	51	13.06
197	Loops in Assembly			255	10.29
83	Graph Generator			391	9.55
404	Methane Normalization		moxieman	5	16.81
90	Lexicographic Permutations			376	9.62
301	Skyscraper Price			126	11.51
403	Hi-Lo dice game			6	16.54
154	Breadth First Search			294	10.04
78	Bezier Curves			378	9.61
117	Divide by Two			321	9.89
99	Uphill Shooting			334	9.82
65	Transitive Closure on Candy States			362	9.68
144	Modular Inverse			273	10.17
155	Depth First Search			258	10.27
174	Calculation of Pi			236	10.42
374	Longest Common Subsequence			34	13.75
408	Mad Beaver in River Labyrinth			-	19.92
161	Topological Sorting			243	10.37
371	Pages to Print			36	13.65
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
384	Equal Hamming Distance		csfpython	21	14.55
76	Pawn Move Validator			291	10.06
96	Snake Arcade			272	10.18
323	Next Palindrome		csfpython	74	12.42
103	Easter Eggs			258	10.27
123	Knapsack of Integers			239	10.40
93	Starving Priority Queue			262	10.24
130	Combinations with Repetitions			228	10.48
84	Dijkstra in the Network			265	10.22
173	Chords of Music			192	10.78
125	Bogosort			231	10.46
360	Whisky Blending		csfpython	39	13.52
368	Number Base Palindrome		csfpython	32	13.85
381	Finding Squares		csfpython	21	14.55
337	Introducing Zeckendorf		csfpython	55	12.93
372	String Minimization			27	14.13
109	Lucky Tickets			226	10.50
146	Color Cubes			198	10.73
151	Word Ladders			190	10.80
208	Neighborhood of a String			145	11.27
402	Game of Stones		csfpython	4	17.13
164	Page Rank			172	10.97
129	Enumerating Combinations			196	10.75
389	Binary Split Guessing Game		csfpython	13	15.34
138	Huffman Coding			186	10.84
364	Arthur Engel's Randomizer			30	13.96
194	Convex Hull and Farmers			147	11.24
390	Card Pairing Solitaire			12	15.47
139	Beam Balance and Masses			182	10.87
329	Roman Arithmetic		csfpython	53	12.99
201	Point in Polygon			138	11.35
199	Employees Web App			139	11.34
359	Find 3 Numbers		csfpython	31	13.90
192	Gangster Battles			136	11.38
152	RSA Cryptography			161	11.09
393	Urban Planning		csfpython	9	15.92
137	Shannon-Fano Coding			169	11.00
111	Necklace Count			176	10.93
244	Introducing SQL			97	11.96
388	Fibonacci Guessing Game			11	15.61
110	Lucky Tickets Advanced			166	11.03
168	Caesar meets BF			133	11.42
398	Collecting Diamonds		csfpython	5	16.81
245	Aggregations in SQL			86	12.17
269	Fibonacci coding			73	12.45
202	Dancing Pairs			108	11.77
179	Look and Say binary			119	11.61
198	Prn Hex Str			109	11.76
162	Rubik's Cube			126	11.51
148	Public Key Cryptography Intro			133	11.42
214	Sick Travellers			99	11.92
124	Knapsack Backtracking			142	11.30
182	Frodo and Black Riders			112	11.71
106	Random Search Optimization			149	11.22
253	Beautiful Line Chart			75	12.40
177	Nim Game			112	11.71
386	Advent Calendar Chocolate		gardengnome	10	15.76
185	Simple 3D Scene			106	11.81
160	Social Web Scraper			117	11.64
392	Fixing an Anagram			7	16.31
294	Vigenere Cipher			52	13.03
102	Travelling Salesman			139	11.34
157	Emirp primE			113	11.70
158	Hamming Codes			111	11.73
258	Text Justification			65	12.65
246	Joins in SQL			70	12.52
395	Growth of Micro-Organisms		csfpython	5	16.81
291	Squirrels vs. Acorns		zelevin	49	13.13
159	Hard Life			103	11.86
281	Basic Tokenizer			51	13.06
196	Fibonacci Randomizer			85	12.19
265	Update in SQL			57	12.87
277	The Adventure of Morse Code		zelevin	52	13.03
379	Dice with Infinity Sides		telebashna	11	15.61
153	Fermat goes hacking RSA			99	11.92
351	Nicomachus			21	14.55
100	Crossing the Road			115	11.67
115	Gradient Descent for SLE			109	11.76
186	Simple 3D Scene (cont)			82	12.25
141	Sliding Window Search			97	11.96
335	Venus Visible			26	14.20
376	Cartesian Tree Visualization			11	15.61
210	Ticket Puzzle			69	12.54
209	Suffix Array Advanced			69	12.54
383	E2C2S - try harder!		gardengnome	8	16.11
166	Page Rank as Eigenvector			83	12.23
193	Maximum Flow			73	12.45
142	LZ77 decompression			89	12.11
203	Tic-Tac-Toe Minimax Algorithm			68	12.57
394	Many Shortest Routes		csfpython	4	17.13
397	Trading Bot			3	17.52
219	Neural Network Calculation			61	12.75
375	Space Invaders			10	15.76
112	Travelling Salesman Inverted			92	12.05
216	Cracking Linear Congruential Generator			59	12.81
363	Language Detector			13	15.34
113	Ground Zero			89	12.11
274	Two Buckets			40	13.47
352	Hurkle			16	15.00
315	Count the Common Factors		csfpython	27	14.13
382	Die Throw Sequences		csfpython	7	16.31
334	Find all of the SETs		csfpython	21	14.55
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
367	Roguelike 1d			11	15.61
293	Sums of Triplets			32	13.85
205	Clustering the Stars			56	12.90
200	Fizz Buzz in Asm			57	12.87
387	Big Numbers		csfpython	5	16.81
354	Too Many Divisors		csfpython	14	15.22
107	Knight's Tour			81	12.27
230	Move-To-Front Transform			47	13.20
353	Hurkle Hunter			14	15.22
204	Wandering Star			53	12.99
212	BCD to Hex			50	13.09
347	Unwanted Multiples		csfpython	15	15.11
292	Factorial Trailing Zeroes			29	14.01
241	Village Ways			42	13.39
330	Easter Bunnies Are Back		gardengnome	19	14.72
257	Missing Records in SQL			36	13.65
218	Rain Must Fall	DE		45	13.27
346	Long Decimal Fractions		csfpython	14	15.22
358	Mandelbrot Set			11	15.61
307	The Problem of Too Many Clues		zelevin	23	14.40
149	Prime Chains			60	12.78
357	Ulam's Prime Spiral			11	15.61
396	Chocolate Triangles and BF		moxieman	2	18.01
361	Rogue Mazes			10	15.76
233	Language Study			39	13.52
378	Space Invaders Automation			6	16.54
338	Throwing Easter Eggs		gardengnome	15	15.11
391	Scout Proficiency Badges		csfpython	3	17.52
349	Burrows		gardengnome	12	15.47
178	Maze of the Wumpus			49	13.13
147	Color Cubes Advanced			55	12.93
362	Euclid, Manhattan and Chebyshev			9	15.92
324	Merge Sort			17	14.90
380	Treap Study			5	16.81
118	Maxit Single-Player			59	12.81
180	Simple Game of Sticks			46	13.24
331	Rotating Toy Display		csfpython	15	15.11
223	Introducing Scheme			37	13.60
297	Collatz in the Range			21	14.55
299	Tree Visualizer			20	14.63
229	Burrows-Wheeler Transform			33	13.80
287	Palindrome Frog		csfpython	22	14.48
340	Zeckendorf Lite		csfpython	12	15.47
255	LCM of a range			28	14.07
183	Connect Four			41	13.43
296	Tree Value	RU	csfpython	20	14.63
339	Parking Lot			12	15.47
247	Towers of Hanoi			29	14.01
313	Seven Segment Decoder			16	15.00
312	The Shredder Conundrum		zelevin	16	15.00
298	Revoltle		zelevin	18	14.81
344	Throwing Easter Eggs Part 2		gardengnome	10	15.76
270	Hexlife			22	14.48
261	Easter Bunnies 2D		gardengnome	23	14.40
341	Zeckendorf Advanced		csfpython	10	15.76
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
249	Turing Increment			24	14.33
217	Personality Swap			29	14.01
332	Easter Bunnies 2D Are Back		gardengnome	11	15.61
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
268	Logic Transformation			19	14.72
275	Three Buckets			18	14.81
169	Automated Landing			33	13.80
300	Run-Length Encoding			14	15.22
285	Rotate Matrix In Place			16	15.00
314	The Sorites Solution		zelevin	12	15.47
343	Village of Ticks			8	16.11
350	Colourful Egg Sequences		gardengnome	7	16.31
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
213	Micro-Life	SK		24	14.33
306	Line Drawing Algorithm			12	15.47
250	Turing Clone			19	14.72
369	Flappy Bird			4	17.13
345	Elliptic Curves Basics			7	16.31
336	Currency Arbitrage			8	16.11
333	Happy Triplets			8	16.11
289	The Case of the Desperate Mastermind		zelevin	13	15.34
220	Neural Network Training			21	14.55
260	Low Cost Road Network		csfpython	16	15.00
365	Flower Border Arrangements		csfpython	4	17.13
303	Towers Under Cover			11	15.61
320	Accordion		pearlbarley	9	15.92
311	The Mirror Maze		zelevin	10	15.76
373	Railroad Rat		csfpython	3	17.52
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
276	Lucky Pairs		csfpython	13	15.34
266	Pancake Sorting			14	15.22
370	Jewels			3	17.52
231	Dice Black Jack			17	14.90
279	Two Buckets Advanced		csfpython	12	15.47
319	Tower of Hanoi Rules		csfpython	8	16.11
328	Beep Beep Beep			7	16.31
254	Rule 30 by Turing			14	15.22
305	The Catacombs of Chronos		zelevin	9	15.92
221	XWords		quandray	17	14.90
325	Ultimate Sort Trial			7	16.31
355	Robots Game			4	17.13
322	Gray Decoder			7	16.31
222	Easter Eggs Advanced			16	15.00
310	Board Game Sequences Advanced		csfpython	8	16.11
342	Adaptive Arithmetic Coding			5	16.81
308	Circle Drawing Algorithm			8	16.11
295	Vigenere Cipher Cracker			9	15.92
235	Train Merge Advanced			14	15.22
304	Ordered Brackets		csfpython	8	16.11
242	Comment Stripper			13	15.34
356	Robots Game Autoplay			3	17.52
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
227	Hashtable Implementation			11	15.61
226	Multiplicative Persistence Backtrace			11	15.61
302	Sound-Controlled Robot			6	16.54
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	17.52
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
228	Maze Mapping Robot			5	16.81
318	Launch to Orbit automated			2	18.01