Problems

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

Volume:

Simple Implementation Algorithms Puzzles Special

all tags

Id	Title	Translations	Author	Solved	Blessing
1	Sum "A+B"	DE ES FR AR ZH RO RU SK		59512	1.00
2	Sum in Loop	DE ES FR AR ZH RO RU SK		36075	1.87
3	Sums in Loop	DE ES FR AR ZH RO RU SK		27509	2.34
4	Minimum of Two	DE ES FR AR ZH RO RU SK		23979	2.58
5	Minimum of Three	DE ES FR AR ZH RO RU SK		21473	2.77
15	Maximum of array	DE ES AR ZH RO RU SK		18770	3.00
6	Rounding	DE ES AR ZH RO RU SK		17210	3.16
7	Fahrenheit to Celsius	DE ES AR ZH RO RU SK		16481	3.23
20	Vowel Count	DE ES AR ZH RO RU SK		13389	3.59
11	Sum of digits	DE ES RU ZH SK		13321	3.60
8	Arithmetic Progression	DE ES RU ZH SK		12514	3.71
41	Median of Three	DE ES AR ZH RO RU SK		11459	3.86
9	Triangles	DE ES RU ZH SK		11957	3.79
28	Body Mass Index	DE ES ZH RU SK		11325	3.88
13	Weighted sum of digits	DE ES RU ZH SK		10814	3.96
43	Dice Rolling	DE ES ZH RU SK		9736	4.14
16	Average of an array	DE ES RU SK		10254	4.05
30	Reverse String	DE ES RU SK		9685	4.15
17	Array Checksum	DE ES RU SK		9529	4.18
21	Array Counters	DE ES RU SK		8875	4.31
10	Linear Function	DE ES RU SK		8624	4.36
48	Collatz Sequence	DE ES RU SK		7701	4.55
12	Modulo and time difference	DE ES RU SK		7832	4.52
14	Modular Calculator	ES SK		7244	4.66
27	Bubble Sort	ES RU SK		6567	4.83
26	Greatest Common Divisor	ES SK RU		6395	4.87
18	Square Root	ES RU		6220	4.92
29	Sort with Indexes	RU		5927	5.01
50	Palindromes	DE ES RU SK		5484	5.14
23	Bubble in Array	ES RU		5683	5.08
52	Pythagorean Theorem	RU		5264	5.21
31	Rotate String	ES RU		5442	5.16
67	Fibonacci Sequence	RU		4722	5.40
68	Bicycle Race	ES RU		4698	5.41
24	Neumann's Random Generator	DE ES RU		5090	5.27
57	Smoothing the Weather	ES RU		4690	5.41
35	Savings Calculator			4503	5.48
104	Triangle Area	ES		3769	5.79
25	Linear Congruential Generator	RU		4450	5.50
44	Double Dice Roll	RU		4218	5.60
32	Josephus Problem	RU		4321	5.56
81	Bit Count	RU		3787	5.78
19	Matching Brackets	ES RU		4099	5.65
58	Card Names			3622	5.86
49	Rock Paper Scissors			3679	5.84
47	Caesar Shift Cipher	SK		3686	5.83
128	Combinations Counting			2988	6.20
55	Matching Words			3541	5.90
94	Fool's Day 2014	SK		3096	6.13
59	Bulls and Cows			3219	6.07
61	Prime Numbers Generation	RU		3158	6.10
22	Two Printers	ES RU		3419	5.96
42	Blackjack Counting			2939	6.23
120	Selection Sort			2321	6.63
38	Quadratic Equation			2722	6.36
33	Parity Control	RU		2652	6.40
53	King and Queen			2377	6.59
34	Binary Search			2462	6.53
171	Tree Height Measurement			1663	7.21
37	Mortgage Calculator	ZH		2307	6.65
45	Cards Shuffling	ZH		2249	6.69
69	Fibonacci Divisibility			2095	6.81
63	Integer Factorization	ZH		2016	6.88
46	Tic-Tac-Toe	ZH		2069	6.83
62	Prime Ranges			1847	7.03
72	Funny Words Generator			1790	7.09
121	Insertion Sort			1552	7.33
75	Yacht or Dice Poker			1690	7.19
172	Cloud Altitude Measurement			1263	7.69
39	Share Price Volatility			1730	7.15
127	Anagrams			1366	7.56
134	Flying Text Screensaver			1282	7.67
156	Luhn Algorithm	SK		1131	7.88
80	Duel Chances			1298	7.64
114	Tricky Printing			1192	7.79
36	Code Guesser	UA		1387	7.53
74	Clock Hands			1222	7.75
135	Variable Length Code			1011	8.08
54	Pythagorean Triples			1208	7.77
105	Convex Polygon Area			1050	8.01
73	Hexagonal Grid			1085	7.96
145	Modular Exponentiation			889	8.30
97	Girls and Pigs			965	8.16
116	Summing Up			869	8.34
181	Reverse Polish Notation			681	8.76
98	Azimuth at Treasure Island			839	8.40
122	QuickSort			778	8.53
51	Dungeons and Dragons Dice	UA		919	8.24
40	Paths in the Grid	UA		930	8.22
85	Rotation in 2D Space			839	8.40
56	Life is Simple			876	8.33
187	Static Web Page			615	8.94
188	Basics of HTML			586	9.02
66	Caesar Cipher Cracker			799	8.49
70	Most Frequent Word			791	8.50
88	Pitch and Notes			742	8.61
87	Tree Builder			708	8.70
108	Star Medals			654	8.83
495	Counting Arithmetic Progressions		csfpython	9	16.10
60	Sweet Harvest			733	8.64
95	Simple Linear Regression			665	8.80
77	Point to Segment Distance			674	8.78
428	Broken Keyboard			113	11.87
499	Binary Frog		csfpython	2	18.19
86	Brainfuck Interpreter			614	8.94
71	Fibonacci Divisibility Advanced			633	8.89
211	Information Entropy			424	9.58
91	Game of 2048			593	9.00
207	Suffix Array			416	9.62
101	Gradient Calculation			547	9.14
143	Extended Euclidean Algorithm			481	9.37
82	Levenshtein Distance			559	9.11
176	Say 100			426	9.58
191	Spaceship Weight Fraud			402	9.68
154	Breadth First Search			438	9.53
89	Instrument Tuner			519	9.23
206	Base-32 Encoding			371	9.82
119	Brain Fibo			476	9.38
64	Maze Pathfinder			543	9.16
79	Cycles Detection			517	9.24
195	Mul Two			373	9.81
480	Coin Payments		csfpython	24	14.51
92	Binary Heap			475	9.39
83	Graph Generator			476	9.38
155	Depth First Search			393	9.72
131	Four Pics One Word			413	9.63
301	Skyscraper Price			216	10.75
485	Magic 3		csfpython	16	15.18
136	Variable Length Code Unpack			375	9.80
78	Bezier Curves			434	9.54
90	Lexicographic Permutations			421	9.60
498	Sum of Divisors Chaining			2	18.19
500	Enchanted Necklace		csfpython	-	20.10
65	Transitive Closure on Candy States			435	9.54
150	Introducing Regexps			350	9.92
126	Sequence of Squares			371	9.82
189	Dynamic Web Page			308	10.14
385	Number of steps in Euclidean Algorithm		gardengnome	111	11.90
167	Copy Line			316	10.09
170	Binary Search in Array			309	10.13
99	Uphill Shooting			369	9.83
476	Prime Vowel Count		csfpython	22	14.65
161	Topological Sorting			311	10.12
197	Loops in Assembly			272	10.35
377	Sum of Digits Divisibility			110	11.92
117	Divide by Two			342	9.96
144	Modular Inverse			312	10.12
494	Holiday Travel		csfpython	5	16.99
487	Reduce and Equalise		csfpython	11	15.78
461	Lucky 7		csfpython	33	13.97
429	Moving Average in Time			59	12.99
425	Explosive Breeding			62	12.90
76	Pawn Move Validator			350	9.92
174	Calculation of Pi			268	10.38
93	Starving Priority Queue			326	10.04
133	Billiard Ball			291	10.24
96	Snake Arcade			313	10.11
140	Proper Bracket Sequences			278	10.32
165	Safe Landing			255	10.47
184	Matches Picking		quandray	234	10.61
103	Easter Eggs			293	10.23
84	Dijkstra in the Network			303	10.17
123	Knapsack of Integers			274	10.34
109	Lucky Tickets			271	10.36
173	Chords of Music			226	10.67
130	Combinations with Repetitions			255	10.47
125	Bogosort			253	10.48
190	Query String Parameters			209	10.81
444	White Rectangle			37	13.78
366	Image Cutting		oezguery	88	12.30
472	Unreachable Amounts		csfpython	18	14.98
481	Field Trip		csfpython	12	15.64
323	Next Palindrome		csfpython	114	11.86
146	Color Cubes			221	10.71
371	Pages to Print			79	12.49
129	Enumerating Combinations			226	10.67
437	Elections and Happiness			38	13.73
471	Missing Digits		csfpython	17	15.08
484	A Message from Deep Space		csfpython	9	16.10
151	Word Ladders			204	10.85
489	TV Charity Fundraiser		csfpython	6	16.72
164	Page Rank			195	10.93
139	Beam Balance and Masses			208	10.82
253	Beautiful Line Chart			142	11.48
433	A Crime on Logic Island		csfpython	38	13.73
208	Neighborhood of a String			167	11.20
360	Whisky Blending		csfpython	79	12.49
374	Longest Common Subsequence			71	12.67
138	Huffman Coding			202	10.87
492	Fastest Clearance		csfpython	4	17.30
194	Convex Hull and Farmers			167	11.20
201	Point in Polygon			161	11.26
337	Introducing Zeckendorf		csfpython	87	12.32
152	RSA Cryptography			183	11.04
111	Necklace Count			204	10.85
137	Shannon-Fano Coding			187	11.00
102	Travelling Salesman			205	10.84
110	Lucky Tickets Advanced			195	10.93
493	Ternary Logic			3	17.69
497	Crazy Timer			1	18.89
192	Gangster Battles			150	11.38
269	Fibonacci coding			112	11.89
399	Methane Identification		moxieman	48	13.34
244	Introducing SQL			122	11.74
199	Employees Web App			142	11.48
329	Roman Arithmetic		csfpython	80	12.46
368	Number Base Palindrome		csfpython	61	12.93
468	The Garden of Words		zelevin	14	15.39
148	Public Key Cryptography Intro			156	11.31
106	Random Search Optimization			172	11.15
124	Knapsack Backtracking			164	11.23
478	Robot Deliveries		csfpython	9	16.10
294	Vigenere Cipher			88	12.30
162	Rubik's Cube			143	11.46
245	Aggregations in SQL			107	11.96
202	Dancing Pairs			125	11.70
482	SS Numbers		csfpython	7	16.49
168	Caesar meets BF			138	11.53
214	Sick Travellers			116	11.83
179	Look and Say binary			130	11.63
449	Space Pirates		csfpython	20	14.81
496	Minimum Journey Cost		csfpython	1	18.89
414	MIDI Variable Length Numbers			33	13.97
182	Frodo and Black Riders			123	11.72
364	Arthur Engel's Randomizer			51	13.23
198	Prn Hex Str			113	11.87
177	Nim Game			119	11.78
258	Text Justification			89	12.28
160	Social Web Scraper			125	11.70
246	Joins in SQL			93	12.21
158	Hamming Codes			125	11.70
490	Circuit Board Connections		csfpython	3	17.69
185	Simple 3D Scene			113	11.87
157	Emirp primE			123	11.72
359	Find 3 Numbers		csfpython	50	13.27
418	Expected Number of Random Moves		moxieman	28	14.25
372	String Minimization			43	13.52
459	Number String Multiples of Thirteen		csfpython	13	15.51
401	Methane Rotation		moxieman	32	14.02
100	Crossing the Road			131	11.62
159	Hard Life			111	11.90
153	Fermat goes hacking RSA			112	11.89
281	Basic Tokenizer			69	12.72
384	Equal Hamming Distance		csfpython	36	13.83
463	Crossing Towns		csfpython	11	15.78
466	Dictionary Entries		csfpython	10	15.93
291	Squirrels vs. Acorns		zelevin	65	12.82
411	Elo Ratings		moxieman	27	14.31
115	Gradient Descent for SLE			119	11.78
265	Update in SQL			72	12.65
488	Accurate Curve Fitting		csfpython	3	17.69
324	Merge Sort			53	13.17
277	The Adventure of Morse Code		zelevin	67	12.77
141	Sliding Window Search			107	11.96
491	Lucky Number Scores		csfpython	2	18.19
447	Fixed Product, Minimum Sum		csfpython	15	15.28
112	Travelling Salesman Inverted			114	11.86
196	Fibonacci Randomizer			89	12.28
460	Carlsdale Caverns		csfpython	11	15.78
186	Simple 3D Scene (cont)			91	12.24
477	Lottery Balls		csfpython	6	16.72
193	Maximum Flow			87	12.32
427	Cheapest Bus Tickets			20	14.81
166	Page Rank as Eigenvector			94	12.19
210	Ticket Puzzle			81	12.44
142	LZ77 decompression			100	12.08
469	Game of Generals			8	16.28
458	Mountain Panorama		csfpython	11	15.78
209	Suffix Array Advanced			79	12.49
113	Ground Zero			104	12.01
475	Medieval Medicine		zelevin	6	16.72
274	Two Buckets			60	12.96
434	A Crime on Logic Island Advanced		csfpython	17	15.08
452	Implication in Logic			12	15.64
203	Tic-Tac-Toe Minimax Algorithm			78	12.51
216	Cracking Linear Congruential Generator			74	12.60
474	Reachable Amounts		gardengnome	6	16.72
219	Neural Network Calculation			72	12.65
259	Easter Bunnies		gardengnome	60	12.96
457	Railroad and Hamilton			10	15.93
381	Finding Squares		csfpython	29	14.19
107	Knight's Tour			97	12.13
351	Nicomachus			36	13.83
403	Hi-Lo dice game			23	14.58
132	Stream Cipher Breaking			89	12.28
464	Graph to Loops Decomposition			8	16.28
241	Village Ways			61	12.93
400	Memory Check			23	14.58
163	Colliding Balls			79	12.49
467	Permutation Generator		csfpython	7	16.49
293	Sums of Triplets			47	13.37
175	Algae Robot			74	12.60
205	Clustering the Stars			65	12.82
483	Sixes and Sevens		csfpython	3	17.69
406	Wormholes of Cygnus		moxieman	20	14.81
230	Move-To-Front Transform			58	13.02
335	Venus Visible			35	13.87
334	Find all of the SETs		csfpython	35	13.87
445	Formula 1			11	15.78
412	Json Fix			18	14.98
407	River Labyrinth			19	14.89
315	Count the Common Factors		csfpython	38	13.73
218	Rain Must Fall	DE		58	13.02
255	LCM of a range			50	13.27
292	Factorial Trailing Zeroes			42	13.56
204	Wandering Star			60	12.96
442	Chomp			11	15.78
421	Princess and Tiger			15	15.28
486	Two Colour Special Nim		csfpython	2	18.19
446	Hangman			10	15.93
200	Fizz Buzz in Asm			59	12.99
390	Card Pairing Solitaire			21	14.73
435	Maze Mapping API-Robot			12	15.64
149	Prime Chains			67	12.77
212	BCD to Hex			54	13.14
257	Missing Records in SQL			45	13.45
453	SR latch			8	16.28
233	Language Study			49	13.30
118	Maxit Single-Player			70	12.69
436	Avoid the Grid Points		csfpython	11	15.78
307	The Problem of Too Many Clues		zelevin	34	13.92
379	Dice with Infinity Sides		telebashna	21	14.73
423	Russian Dolls		csfpython	13	15.51
473	Skittles		csfpython	4	17.30
180	Simple Game of Sticks			56	13.07
388	Fibonacci Guessing Game			19	14.89
450	Bead Games		csfpython	8	16.28
223	Introducing Scheme			48	13.34
438	Maze Generator			10	15.93
247	Towers of Hanoi			43	13.52
147	Color Cubes Advanced			60	12.96
178	Maze of the Wumpus			54	13.14
376	Cartesian Tree Visualization			20	14.81
229	Burrows-Wheeler Transform			44	13.49
440	Mud Walker			9	16.10
439	Power Sum of Digits		csfpython	9	16.10
420	Life on a String		csfpython	12	15.64
426	Weighted Sum of Digits 2		csfpython	11	15.78
451	Maximize Toy Production		csfpython	7	16.49
299	Tree Visualizer			30	14.13
357	Ulam's Prime Spiral			21	14.73
347	Unwanted Multiples		csfpython	22	14.65
183	Connect Four			46	13.41
352	Hurkle			21	14.73
338	Throwing Easter Eggs		gardengnome	23	14.58
270	Hexlife			33	13.97
330	Easter Bunnies Are Back		gardengnome	24	14.51
389	Binary Split Guessing Game		csfpython	15	15.28
354	Too Many Divisors		csfpython	20	14.81
297	Collatz in the Range			28	14.25
409	Election Fever		csfpython	12	15.64
465	Red Blue Hackenbush		csfpython	4	17.30
284	Rotate Array In-Place			29	14.19
349	Burrows		gardengnome	20	14.81
362	Euclid, Manhattan and Chebyshev			18	14.98
296	Tree Value	RU	csfpython	27	14.31
405	Three Friendly Knights		csfpython	12	15.64
234	Train Merge			35	13.87
256	Rook Jump Maze			31	14.08
455	D flip-flop			5	16.99
286	Self-Printing Program			27	14.31
339	Parking Lot			20	14.81
346	Long Decimal Fractions		csfpython	19	14.89
392	Fixing an Anagram			13	15.51
353	Hurkle Hunter			18	14.98
290	Every Leaf on Every Tree		zelevin	26	14.37
243	Grille Encryption			32	14.02
415	Smallest Message		gardengnome	10	15.93
454	Multiplexer 4x4			5	16.99
287	Palindrome Frog		csfpython	26	14.37
238	Bear Hunt			32	14.02
268	Logic Transformation			28	14.25
340	Zeckendorf Lite		csfpython	19	14.89
217	Personality Swap			34	13.92
249	Turing Increment			30	14.13
312	The Shredder Conundrum		zelevin	22	14.65
261	Easter Bunnies 2D		gardengnome	28	14.25
393	Urban Planning		csfpython	12	15.64
367	Roguelike 1d			15	15.28
417	Unfortunate Bubble Sort		gardengnome	9	16.10
375	Space Invaders			14	15.39
298	Revoltle		zelevin	23	14.58
331	Rotating Toy Display		csfpython	19	14.89
382	Die Throw Sequences		csfpython	13	15.51
169	Automated Landing			38	13.73
432	Ball Bearing Collisions		csfpython	7	16.49
300	Run-Length Encoding			22	14.65
361	Rogue Mazes			15	15.28
395	Growth of Micro-Organisms		csfpython	11	15.78
295	Vigenere Cipher Cracker			22	14.65
275	Three Buckets			24	14.51
383	E2C2S - try harder!		gardengnome	12	15.64
363	Language Detector			14	15.39
250	Turing Clone			26	14.37
408	Mad Beaver in River Labyrinth			9	16.10
398	Collecting Diamonds		csfpython	10	15.93
285	Rotate Matrix In Place			22	14.65
313	Seven Segment Decoder			19	14.89
282	Predictable Board Game		csfpython	22	14.65
319	Tower of Hanoi Rules		csfpython	18	14.98
386	Advent Calendar Chocolate		gardengnome	11	15.78
271	A Knight some Trolls and a Princess		csfpython	23	14.58
462	Rota Boards		csfpython	3	17.69
344	Throwing Easter Eggs Part 2		gardengnome	15	15.28
314	The Sorites Solution		zelevin	18	14.98
402	Game of Stones		csfpython	9	16.10
431	King and Rook Checkmate			6	16.72
260	Low Cost Road Network		csfpython	23	14.58
358	Mandelbrot Set			13	15.51
419	Special Digits		csfpython	7	16.49
470	Shogi Engine			2	18.19
448	Button Cycles		csfpython	4	17.30
341	Zeckendorf Advanced		csfpython	14	15.39
231	Dice Black Jack			24	14.51
479	Robot and the Wall			1	18.89
424	New Towers of Hanoi		csfpython	6	16.72
413	Tree Painting		csfpython	7	16.49
220	Neural Network Training			24	14.51
456	Every Third Bit			3	17.69
213	Micro-Life	SK		24	14.51
443	Football League Tables		csfpython	4	17.30
222	Easter Eggs Advanced			23	14.58
266	Pancake Sorting			19	14.89
336	Currency Arbitrage			13	15.51
441	Max versus Min		csfpython	4	17.30
332	Easter Bunnies 2D Are Back		gardengnome	13	15.51
380	Treap Study			9	16.10
404	Methane Normalization		moxieman	7	16.49
416	Socket Server		testuser	6	16.72
254	Rule 30 by Turing			19	14.89
289	The Case of the Desperate Mastermind		zelevin	16	15.18
263	Easter Bunnies 3D		gardengnome	18	14.98
262	Easter Bunnies 2D Advanced		gardengnome	18	14.98
387	Big Numbers		csfpython	8	16.28
221	XWords		quandray	21	14.73
410	Village Door Shuffle		csfpython	6	16.72
422	Mabinogion Sheep		moxieman	5	16.99
343	Village of Ticks			11	15.78
316	Apogee			13	15.51
235	Train Merge Advanced			19	14.89
288	Langton's Ant		csfpython	15	15.28
326	Sum Them Forth			12	15.64
311	The Mirror Maze		zelevin	13	15.51
309	Board Game Sequences		csfpython	13	15.51
350	Colourful Egg Sequences		gardengnome	10	15.93
391	Scout Proficiency Badges		csfpython	7	16.49
267	Turing Maze			16	15.18
279	Two Buckets Advanced		csfpython	15	15.28
320	Accordion		pearlbarley	12	15.64
306	Line Drawing Algorithm			13	15.51
333	Happy Triplets			11	15.78
305	The Catacombs of Chronos		zelevin	13	15.51
276	Lucky Pairs		csfpython	15	15.28
304	Ordered Brackets		csfpython	13	15.51
303	Towers Under Cover			13	15.51
345	Elliptic Curves Basics			10	15.93
430	Cutting Paper		csfpython	4	17.30
342	Adaptive Arithmetic Coding			10	15.93
369	Flappy Bird			8	16.28
264	Party Presents		csfpython	15	15.28
365	Flower Border Arrangements		csfpython	8	16.28
242	Comment Stripper			16	15.18
394	Many Shortest Routes		csfpython	6	16.72
224	Transposing List of Lists			17	15.08
237	Road Network Destruction			16	15.18
310	Board Game Sequences Advanced		csfpython	11	15.78
373	Railroad Rat		csfpython	7	16.49
227	Hashtable Implementation			16	15.18
322	Gray Decoder			10	15.93
321	Hanoi Tower Heights		csfpython	10	15.93
397	Trading Bot			5	16.99
327	Dobbin's Long Journey		csfpython	9	16.10
378	Space Invaders Automation			6	16.72
325	Ultimate Sort Trial			9	16.10
302	Sound-Controlled Robot			10	15.93
283	Predictable Board Game on 10 Boards		csfpython	11	15.78
225	Hamurabi			14	15.39
252	Shadok and Gibis			12	15.64
328	Beep Beep Beep			8	16.28
308	Circle Drawing Algorithm			9	16.10
278	Polyomino Generation			10	15.93
215	Klotski	SK		13	15.51
251	Radio Spies			11	15.78
370	Jewels			5	16.99
280	Three Buckets Re-visited		csfpython	9	16.10
232	Shift Register Randomizer			11	15.78
273	Logic Glitches			9	16.10
226	Multiplicative Persistence Backtrace			11	15.78
236	Is the Earth Flat			10	15.93
248	Christmas Puzzle			9	16.10
348	Trick-Taking Game			5	16.99
240	Playfair Cipher Cracking			9	16.10
239	Foxes and Geese			9	16.10
396	Chocolate Triangles and BF		moxieman	3	17.69
272	Hexplore			7	16.49
355	Robots Game			4	17.30
228	Maze Mapping Robot			8	16.28
317	Launch to Orbit			5	16.99
356	Robots Game Autoplay			3	17.69
318	Launch to Orbit automated			2	18.19