Codeforces problemset search & solutions
Exclude tags.

Review the problem statement from Codeforces (link will open a new tab). When you've matched your problem, go to the solutions.

Search on plain tags, ratings, names, and problem text. Example: brute force or binary search

1 2 >

Solved
Name
Tags
Solutions
Index
Contest
Type
Points
Tutorial
Rating Level
995 Quest dp greedy Statement F VK Cup 2015 - Round 3 (unofficial online mirror, Div. 1 only) {542} PROGRAMMING 17697 2100
0 Scheduler for Invokers *special Statement A VK Cup 2016 - Wild Card Round 2 {642} PROGRAMMING 2900
15378 Bear and Prime 100 constructive algorithms interactive math Statement A Codeforces Round 356 (Div. 1) {679} PROGRAMMING Codeforces Round #356 — Editorial 1400
1503 Searching Rectangles binary search constructive algorithms interactive Statement B Codeforces Round 371 (Div. 1) {713} PROGRAMMING Codeforces Round #371 Editorial 2200
8913 Guess the Array constructive algorithms interactive math Statement C Technocup 2017 - Elimination Round 1 (Unofficially Open for Everyone, Rated for Div. 2) {727} PROGRAMMING Tutorial 1400
2771 Minimum and Maximum constructive algorithms interactive Statement B 2016-2017 ACM-ICPC, NEERC, Southern Subregional Contest (Online Mirror, ACM-ICPC Rules, Teams Preferred) {730} PROGRAMMING Разбор задач (видео, по-русски) 1900
1948 Hongcow's Game bitmasks divide and conquer interactive Statement B Codeforces Round 385 (Div. 1) {744} PROGRAMMING Codeforces Round #385 Editorial 2000
592 New Year and Finding Roots constructive algorithms implementation interactive trees Statement F Good Bye 2016 {750} PROGRAMMING Good Bye 2016 — hints and codes 2700
238 New Year and Snowy Grid dfs and similar dsu graphs interactive Statement H Good Bye 2016 {750} PROGRAMMING Good Bye 2016 — hints and codes 3400
1434 Interactive Bulls and Cows (Easy) brute force constructive algorithms implementation Statement B Testing Round 13 {753} PROGRAMMING 1600
396 Interactive Bulls and Cows (Hard) brute force constructive algorithms interactive Statement C Testing Round 13 {753} PROGRAMMING 2400
14941 PolandBall and Forest dfs and similar dsu graphs interactive trees Statement C 8VC Venture Cup 2017 - Elimination Round {755} PROGRAMMING 8VC Venture Cup 2017 — Elimination Round [Editorial] 1300
219 Verifying Kingdom binary search divide and conquer interactive trees Statement E VK Cup 2017 - Round 2 {772} PROGRAMMING VK Cup Round 2 + Codeforces Round #409 Tutorial 3200
409 Finding lines constructive algorithms divide and conquer interactive Statement D Codeforces Round 407 (Div. 1) {788} PROGRAMMING Codeforces Round #407(Div.1 + Div.2) Editorial 2900
1772 Glad to see you! binary search interactive Statement B Codeforces Round 415 (Div. 1) {809} PROGRAMMING 52099 2200
1900 Vladik and Favorite Game constructive algorithms dfs and similar graphs interactive Statement D Codeforces Round 416 (Div. 2) {811} PROGRAMMING 2000
1346 The penguin's game binary search constructive algorithms interactive Statement E Codeforces Round 427 (Div. 2) {835} PROGRAMMING 2400
2569 Interactive LowerBound brute force interactive probabilities Statement B AIM Tech Round 4 (Div. 1) {843} PROGRAMMING AIM Tech Round 4 -- Editorial 2000
2036 Mahmoud and Ehab and the binary string binary search divide and conquer interactive Statement D Codeforces Round 435 (Div. 2) {862} PROGRAMMING Codeforces round #435 editorial 2000
1291 Something with XOR Queries brute force interactive probabilities Statement D Technocup 2018 - Elimination Round 2 {870} PROGRAMMING Editorial Codeforces Round 440 Div.1+Div.2 (and Technocup 2018 — Elimination Round 2) 2100
2294 Ithea Plays With Chtholly binary search constructive algorithms games greedy interactive Statement B Codeforces Round 449 (Div. 1) {896} PROGRAMMING Codeforces Round #449 Editorial 2000
562 Jamie and To-do List data structures interactive trees Statement D Codeforces Round 457 (Div. 2) {916} PROGRAMMING Codeforces Round #457 (Div. 2) Editorial 2600
1 BuberPool Taxi Optimization Statement A VK Cup 2018 - Wild-card Round 2 {927} PROGRAMMING 2800
2115 A Map of the Cat brute force Statement B April Fools Contest 2018 {952} PROGRAMMING April Fools Day Contest 2018: editorial 1800
527 Guess two numbers binary search interactive Statement C Codeforces Round 497 (Div. 1) {1007} PROGRAMMING Editorial for Codeforces Round #497 by Skyglow 2800
6370 Rocket binary search interactive Statement B Codeforces Round 499 (Div. 1) {1010} PROGRAMMING 60851 1800
2110 The hat binary search interactive Statement B Codeforces Round 503 (by SIS, Div. 1) {1019} PROGRAMMING 61161 2200
2217 Down or Right constructive algorithms interactive matrices Statement E Codeforces Round 504 (rated, Div. 1 + Div. 2, based on VK Cup 2018 Final) {1023} PROGRAMMING Codeforces Round 504 Editorial 2100
644 Guess the number dp interactive Statement G AIM Tech Round 5 (rated, Div. 1 + Div. 2) {1028} PROGRAMMING 61493 2900
2606 Divisors interactive math number theory Statement D Lyft Level 5 Challenge 2018 - Elimination Round {1033} PROGRAMMING The Lyft Level 5 Challenge 2018 Elimination Round (Div. 1 + Div. 2) Editorial 2000
787 Hidden Bipartite Graph binary search constructive algorithms dfs and similar graphs interactive Statement E Lyft Level 5 Challenge 2018 - Elimination Round {1033} PROGRAMMING The Lyft Level 5 Challenge 2018 Elimination Round (Div. 1 + Div. 2) Editorial 2700
2582 Subway Pursuit binary search interactive probabilities Statement B Codeforces Round 507 (Div. 1, based on Olympiad of Metropolises) {1039} PROGRAMMING 61668 2100
1706 Intersecting Subtrees dfs and similar interactive trees Statement B Lyft Level 5 Challenge 2018 - Final Round {1044} PROGRAMMING Lyft Level 5 Challenge 2018 — Final Round — Editorial 1900
2571 Pick Heroes greedy implementation interactive sortings Statement C Mail.Ru Cup 2018 Round 3 {1056} PROGRAMMING Mail.Ru Cup 2018 Round 3 Editorial 1700
885 Lost Root interactive probabilities Statement F Codeforces Round 523 (Div. 2) {1061} PROGRAMMING Tutorial (en) 2400
3275 Dwarves, Hats and Extrasensory Abilities binary search constructive algorithms geometry interactive Statement C Codeforces Round 516 (Div. 1, by Moscow Team Olympiad) {1063} PROGRAMMING 1900
913 Katya and Segments Sets data structures interactive sortings Statement F Codeforces Round 524 (Div. 2) {1080} PROGRAMMING Codeforces Round #524 (Div. 2) Editorial 2700
505 Tricky Interactor constructive algorithms implementation interactive Statement F Avito Cool Challenge 2018 {1081} PROGRAMMING 63888 2500
3160 Ehab and another another xor problem bitmasks constructive algorithms implementation interactive Statement D Codeforces Round 525 (Div. 2) {1088} PROGRAMMING Codeforces round #525 editorial 2000
458 Cactus Search interactive Statement C 2018-2019 ICPC, NEERC, Northern Eurasia Finals (Unrated, Online Mirror, ICPC Rules, Teams Preferred) {1089} PROGRAMMING 2800
227 New Year and the Factorisation Collaboration interactive math number theory Statement G Good Bye 2018 {1091} PROGRAMMING Editorial 3100
915 Dasha and Chess constructive algorithms games interactive Statement D Codeforces Round 532 (Div. 2) {1100} PROGRAMMING Unofficial Tutorial 2400
3521 Game with modulo binary search constructive algorithms interactive Statement B Codeforces Round 534 (Div. 1) {1103} PROGRAMMING Codeforces Round #534 — Editorial 2000
3181 Arithmetic Progression binary search interactive number theory probabilities Statement E Codeforces Round 538 (Div. 2) {1114} PROGRAMMING Codeforces Round #538 (Div. 2) Editorial 2100
1635 Decypher the String bitmasks chinese remainder theorem constructive algorithms interactive math Statement E Educational Codeforces Round 60 (Rated for Div. 2) {1117} PROGRAMMING 65365 2200
565 Legendary Tree binary search interactive trees Statement E Codeforces Round 542 [Alex Lopashev Thanks-Round] (Div. 1) {1129} PROGRAMMING 65520 3000
2141 Cooperative Game constructive algorithms interactive number theory Statement D Codeforces Round 545 (Div. 1) {1137} PROGRAMMING Codeforces Round #545 – Editorial 2500
632 Pink Floyd graphs interactive Statement E Codeforces Round 549 (Div. 1) {1142} PROGRAMMING Codeforces Round #549 Editorial 3100
190 AI Takeover Statement G April Fools Day Contest 2019 {1145} PROGRAMMING 66327
4195 Tree Diameter bitmasks graphs interactive Statement C Forethought Future Cup - Elimination Round {1146} PROGRAMMING 66639 1700
471 Rainbow Coins interactive Statement E Forethought Future Cup - Final Round (Onsite Finalists Only) {1147} PROGRAMMING Forethought Future Cup Final Round Tutorial 2900
337 Zigzag Game games interactive Statement F Forethought Future Cup - Final Round (Onsite Finalists Only) {1147} PROGRAMMING Forethought Future Cup Final Round Tutorial 3400
1754 Serval and Snake binary search brute force interactive Statement E Codeforces Round 551 (Div. 2) {1153} PROGRAMMING Editorial 2100
1598 Guess the Root brute force interactive math Statement E Educational Codeforces Round 63 (Rated for Div. 2) {1155} PROGRAMMING 66687 2200
193 Strange device binary search interactive math trees Statement E Codeforces Round 559 (Div. 1) {1158} PROGRAMMING 66993 3300
16349 Lost Numbers brute force divide and conquer interactive math Statement B Educational Codeforces Round 65 (Rated for Div. 2) {1167} PROGRAMMING 67058 1400
1956 Ehab and the Big Finale constructive algorithms divide and conquer graphs implementation interactive trees Statement F Codeforces Round 563 (Div. 2) {1174} PROGRAMMING Codeforces round #563 editorial 2300
198 Alesya and Discrete Math divide and conquer interactive Statement E Codeforces Round 569 (Div. 1) {1179} PROGRAMMING Editorial of Round #569 3200
146 Knightmare (easy) graphs interactive shortest paths Statement E1 Codeforces Round 577 (Div. 2) {1201} PROGRAMMING Codeforces Round #577 (Div 2) Editorial 2900
165 Knightmare (hard) graphs interactive shortest paths Statement E2 Codeforces Round 577 (Div. 2) {1201} PROGRAMMING Codeforces Round #577 (Div 2) Editorial 3000
1256 Palindromic Paths implementation interactive Statement C Codeforces Round 580 (Div. 1) {1205} PROGRAMMING 69158 2500
6631 XOR Guessing bitmasks interactive math Statement E Educational Codeforces Round 71 (Rated for Div. 2) {1207} PROGRAMMING Educational Codeforces Round 71 Editorial 1800
1591 Point Ordering constructive algorithms geometry interactive math Statement C Codeforces Round 601 (Div. 1) {1254} PROGRAMMING Codeforces Round #601 Editorial 2300
1068 Intriguing Selection brute force constructive algorithms implementation interactive sortings Statement I 2019-2020 ICPC, NERC, Northern Eurasia Finals (Unrated, Online Mirror, ICPC Rules, Teams Preferred) {1267} PROGRAMMING nerc-2019-tutorial.pdf 2700
4862 Strange Device constructive algorithms interactive math sortings Statement D Good Bye 2019 {1270} PROGRAMMING Разбор Goodbye 2019 1900
92 Шардирование постов *special binary search interactive Statement F VK Cup 2019 - Квалификация (Engine) {1275} PROGRAMMING 3000.0
2371 Enchanted Artifact constructive algorithms interactive strings Statement D Codeforces Round 610 (Div. 2) {1282} PROGRAMMING 72461 2300
1577 Madhouse (Easy version) brute force constructive algorithms interactive math Statement C1 Codeforces Round 612 (Div. 1) {1286} PROGRAMMING Codeforces Round #612 - Editorial 2400
744 Madhouse (Hard version) brute force constructive algorithms hashing interactive math Statement C2 Codeforces Round 612 (Div. 1) {1286} PROGRAMMING Codeforces Round #612 - Editorial 2900
947 Coffee Varieties (hard version) constructive algorithms graphs interactive Statement D Codeforces Round 616 (Div. 1) {1290} PROGRAMMING 2500.0 Codeforces Round #616 Editorial 2900
726 Coffee Varieties (easy version) graphs interactive Statement F Codeforces Round 616 (Div. 2) {1291} PROGRAMMING 3000.0 Codeforces Round #616 Editorial 2700
462 Rin and The Unknown Flower constructive algorithms greedy interactive math Statement E Codeforces Round 614 (Div. 1) {1292} PROGRAMMING 2250.0 Codeforces Round #614 Editorial 3500
189 So Mean interactive math Statement E Codeforces Round 618 (Div. 1) {1299} PROGRAMMING 2250.0 Codeforces Round #618 Editorial 3400
5354 Kuroni and the Celebration constructive algorithms dfs and similar graphs interactive trees Statement D Ozon Tech Challenge 2020 (Div.1 + Div.2, Rated, T-shirts + prizes!) {1305} PROGRAMMING 1750.0 Ozon Tech Challenge 2020 Editorial 1900
524 Yui and Mahjong Set constructive algorithms interactive Statement D Codeforces Round 635 (Div. 1) {1336} PROGRAMMING 2250.0 Codeforces Round #635 Editorial 3000
101 Nastya and Bees graphs interactive probabilities Statement E Codeforces Round 637 (Div. 1) - Thanks, Ivan Belonogov! {1340} PROGRAMMING 2250.0 Codeforces Round #637 Editorial
952 Find a Gift binary search interactive probabilities Statement G Educational Codeforces Round 87 (Rated for Div. 2) {1354} PROGRAMMING 77593 2600
959 Guess Divisors Count constructive algorithms interactive number theory Statement F Codeforces Round 643 (Div. 2) {1355} PROGRAMMING 3000.0 Codeforces Round #643 (Div. 2) Editorial 2600
4405 Guess The Maximums binary search divide and conquer implementation interactive math Statement D Codeforces Round 646 (Div. 2) {1363} PROGRAMMING 2000.0 78202 2100
1546 X-OR bitmasks constructive algorithms interactive probabilities Statement E Codeforces Round 649 (Div. 2) {1364} PROGRAMMING 2500.0 Codeforces round #649 editorial 2700
1413 Secure Password bitmasks combinatorics constructive algorithms interactive math Statement G Codeforces Round 648 (Div. 2) {1365} PROGRAMMING 3000.0 Editorial — Codeforces Round #648 2800
1104 Lamps on a Circle games greedy implementation interactive math Statement F Codeforces Global Round 8 {1368} PROGRAMMING 3000.0 Codeforces Global Round 8: editorial
1779 The Hidden Pair (Easy Version) binary search dfs and similar graphs interactive shortest paths trees Statement F1 Codeforces Round 651 (Div. 2) {1370} PROGRAMMING 2000.0 Editorial — Codeforces Round #651
1662 The Hidden Pair (Hard Version) binary search dfs and similar graphs interactive shortest paths trees Statement F2 Codeforces Round 651 (Div. 2) {1370} PROGRAMMING 1250.0 Editorial — Codeforces Round #651
494 Omkar and Modes interactive Statement F Codeforces Round 655 (Div. 2) {1372} PROGRAMMING 3000.0 Codeforces Round #655 Editorial 2800
2502 Integer Game brute force constructive algorithms games interactive math Statement F Codeforces Global Round 9 {1375} PROGRAMMING 2000.0 79731
349 Colors *special binary search constructive algorithms interactive Statement A Baltic Olympiad in Informatics 2020, Day 1 (IOI, Unofficial Mirror Contest, Unrated) {1386} PROGRAMMING T
3736 Omkar and Duck bitmasks constructive algorithms interactive math Statement E Codeforces Global Round 10 {1392} PROGRAMMING 2000.0 Codeforces Global Round 10 — Editorial
312 The Potion of Great Power *special binary search data structures graphs interactive sortings two pointers Statement A Central-European Olympiad in Informatics, CEOI 2020, Day 2 (IOI, Unofficial Mirror Contest, Unrated) {1403} PROGRAMMING CEOI 2020 Online Mirror — Day 2 Tutorial
1269 Game of Pairs constructive algorithms dfs and similar interactive math number theory Statement D Codeforces Round 668 (Div. 1) {1404} PROGRAMMING 2250.0 Codeforces Round #668 Editorial
1864 Deleting Numbers binary search brute force interactive number theory Statement E Codeforces Round 670 (Div. 2) {1406} PROGRAMMING 2750.0 Codeforces Round #670 (Div. 2) Editorial
14616 Chocolate Bunny constructive algorithms interactive math two pointers Statement C Codeforces Round 669 (Div. 2) {1407} PROGRAMMING 1500.0 Codeforces Round #669 Editorial
323 Milutin's Plums interactive Statement M Bubble Cup 13 - Finals [Online Mirror, unrated, Div. 1] {1423} PROGRAMMING FinalsEditorial2020.pdf
7147 Flamingoes of Mystery interactive Statement F 2020 ICPC, COMPFEST 12, Indonesia Multi-Provincial Contest (Unrated, Online Mirror, ICPC Rules, Teams Preferred) {1425} PROGRAMMING Tutorial 1400
127 Rotary Laser Lock binary search interactive Statement H Codeforces Raif Round 1 (Div. 1 + Div. 2) {1428} PROGRAMMING 4000.0 Codeforces Raif Round 1 Editorial
800 Olha and Igor interactive trees Statement F Codeforces Round 682 (Div. 2) {1438} PROGRAMMING 3000.0 Codeforces Round #682 (Div. 2) Editorial
169 Differentiating Games games interactive Statement F Codeforces Round 681 (Div. 1, based on VK Cup 2019-2020 - Final) {1442} PROGRAMMING 2500.0 84298
166 Finding the Vertex brute force dfs and similar dp interactive trees Statement E Codeforces Round 680 (Div. 1, based on Moscow Team Olympiad) {1444} PROGRAMMING 3000.0 Codeforces Round #680 Editorial
4894 Bitwise Queries (Easy Version) bitmasks constructive algorithms interactive math Statement E1 Codeforces Round 685 (Div. 2) {1451} PROGRAMMING 1500.0 Editorial — Codeforces Round #685
3359 Bitwise Queries (Hard Version) bitmasks constructive algorithms interactive math Statement E2 Codeforces Round 685 (Div. 2) {1451} PROGRAMMING 1000.0 Editorial — Codeforces Round #685
232 The Riddle of the Sphinx binary search data structures data structures interactive Statement I Good Bye 2020 {1466} PROGRAMMING 4000.0 Good Bye 2020 Editorial
1436 Strange Shuffle binary search brute force constructive algorithms interactive probabilities Statement C Codeforces Round 694 (Div. 1) {1470} PROGRAMMING 1000.0 86464
13055 Searching Local Minimum binary search interactive ternary search Statement A Codeforces Round 700 (Div. 1) {1479} PROGRAMMING 500.0 Editorial of Codeforces Round #700
344 Vabank binary search interactive Statement G Технокубок 2021 - Финал {1482} PROGRAMMING 3500.0 Technocup 2021: Final Round and Codeforces Round #709 — tutorial
41 Vabank binary search interactive Statement E Codeforces Round 709 (Div. 1, based on Technocup 2021 Final Round) {1483} PROGRAMMING 2500.0 Technocup 2021: Final Round and Codeforces Round #709 — tutorial
14200 Guessing the Greatest (easy version) binary search interactive Statement C1 Codeforces Round 703 (Div. 2) {1486} PROGRAMMING 750.0 Codeforces Round #703 (Div. 2) Editorial
9931 Guessing the Greatest (hard version) binary search interactive Statement C2 Codeforces Round 703 (Div. 2) {1486} PROGRAMMING 750.0 Codeforces Round #703 (Div. 2) Editorial
1130 Magnets binary search constructive algorithms interactive Statement F Codeforces Global Round 13 {1491} PROGRAMMING 2000.0 Codeforces Global Round 13 Editorial
501 Enchanted Matrix bitmasks interactive number theory Statement F Codeforces Round 705 (Div. 2) {1493} PROGRAMMING 3250.0 Codeforces Round #705 (Div.2) Editorial
2110 Two Houses brute force combinatorics graphs interactive probabilities sortings Statement E CodeCraft-21 and Codeforces Round 711 (Div. 2) {1498} PROGRAMMING 2500.0 CodeCraft-21 and Codeforces Round #711 (Div. 2) Editorial
236 Graph Coloring data structures graphs interactive Statement G Educational Codeforces Round 106 (Rated for Div. 2) {1499} PROGRAMMING Educational Codeforces Round 106 Editorial
7667 3-Coloring constructive algorithms games interactive Statement B Codeforces Round 712 (Div. 1) {1503} PROGRAMMING 1000.0 T 1700
16051 Is it rated - 2 implementation interactive Statement A April Fools Day Contest 2021 {1505} PROGRAMMING tutorial
583 Is It Rated? greedy interactive math probabilities Statement I 2020-2021 ICPC, NERC, Northern Eurasia Onsite (Unrated, Online Mirror, ICPC Rules, Teams Preferred) {1510} PROGRAMMING nerc-2020-offline-tutorial.pdf
695 Baby Ehab's Hyper Apartment binary search graphs interactive sortings Statement E Codeforces Round 716 (Div. 2) {1514} PROGRAMMING 2500.0 Codeforces round #716 editorial
3332 Guess the K-th Zero (Hard version) binary search data structures interactive Statement F2 Codeforces Round 719 (Div. 3) {1520} PROGRAMMING Editorial
14324 Guess the K-th Zero (Easy version) binary search interactive Statement F1 Codeforces Round 719 (Div. 3) {1520} PROGRAMMING Editorial
4603 Nastia and a Hidden Permutation constructive algorithms interactive Statement C Codeforces Round 720 (Div. 2) {1521} PROGRAMMING 1750.0 90477
388 Median Queries constructive algorithms interactive probabilities Statement F Codeforces Round 723 (Div. 2) {1526} PROGRAMMING 3500.0 Codeforces Round #723 (Div. 2) Editorial
2073 Lost Array constructive algorithms dp graphs interactive shortest paths Statement E Codeforces LATOKEN Round 1 (Div. 1 + Div. 2) {1534} PROGRAMMING 2250.0 Codeforces LATOKEN Round 1 (Div. 1 + Div. 2) Editorial
6785 Lost Tree constructive algorithms interactive trees Statement D Codeforces LATOKEN Round 1 (Div. 1 + Div. 2) {1534} PROGRAMMING 1500.0 Codeforces LATOKEN Round 1 (Div. 1 + Div. 2) Editorial
255 Lost Nodes dp graphs interactive sortings trees Statement H Codeforces LATOKEN Round 1 (Div. 1 + Div. 2) {1534} PROGRAMMING 3500.0 Codeforces LATOKEN Round 1 (Div. 1 + Div. 2) Editorial
3059 Gold Transfer binary search data structures greedy interactive trees Statement E Educational Codeforces Round 110 (Rated for Div. 2) {1535} PROGRAMMING 91481
7995 RPD and Rap Sheet (Easy Version) bitmasks constructive algorithms interactive math Statement D1 Codeforces Round 730 (Div. 2) {1543} PROGRAMMING 1000.0 Codeforces Round #730 (Div. 2) Editorial
2162 RPD and Rap Sheet (Hard Version) constructive algorithms dp interactive math Statement D2 Codeforces Round 730 (Div. 2) {1543} PROGRAMMING 1250.0 Codeforces Round #730 (Div. 2) Editorial
605 AquaMoon and Wrong Coordinate constructive algorithms interactive math Statement D Codeforces Round 732 (Div. 1) {1545} PROGRAMMING 2250.0 Codeforces Round #732 Editorial 3000
13935 AquaMoon and Stolen String interactive Statement B Codeforces Round 732 (Div. 2) {1546} PROGRAMMING 1000.0 Codeforces Round #732 Editorial 1200
458 Guess the Perimeter binary search interactive number theory Statement H Codeforces Global Round 15 {1552} PROGRAMMING 2750.0 Editorial of Global Round 15
8548 Take a Guess bitmasks constructive algorithms interactive math Statement D Deltix Round, Summer 2021 (open for everyone, rated, Div. 1 + Div. 2) {1556} PROGRAMMING 1500.0 94384 1800
762 Assiut Chess brute force interactive probabilities two pointers Statement E Codeforces Round 737 (Div. 2) {1557} PROGRAMMING 3000.0 Codeforces Round #737 Editorial
453 Tubular Bells interactive math number theory probabilities Statement F Codeforces Round 741 (Div. 2) {1562} PROGRAMMING 3500.0 Editorial of Codeforces Round 741 (Div. 2)
152 Xor-quiz constructive algorithms dp interactive math number theory Statement H Codeforces Global Round 16 {1566} PROGRAMMING 3750.0 Codeforces Global Round 16 Editorial
143 XOR Guessing *special interactive Statement G Kotlin Heroes: Practice 8 {1570} PROGRAMMING
508 The Mind constructive algorithms interactive probabilities Statement M ICPC WF Moscow Invitational Contest - Online Mirror (Unrated, ICPC Rules, Teams Preferred) {1578} PROGRAMMING Tutorial (PDF)
72 Interactive Rays geometry interactive Statement I ICPC WF Moscow Invitational Contest - Online Mirror (Unrated, ICPC Rules, Teams Preferred) {1578} PROGRAMMING Tutorial (PDF)
5928 Omkar and the Meaning of Life constructive algorithms interactive Statement D Technocup 2022 - Elimination Round 1 {1583} PROGRAMMING 1750.0 Editorial for Technocup 2022 — Elimination Round 1 and Codeforces Round #749 (Div. 1+Div. 2)
3983 Guess the Permutation binary search combinatorics interactive math Statement D Technocup 2022 - Elimination Round 2 {1584} PROGRAMMING 1500.0 Editorial for Technocup 2022 — Elimination Round 2 and Codeforces Round #755 (Div. 1, Div. 2) 2000
2551 Hemose in ICPC ? binary search dfs and similar divide and conquer interactive math number theory trees Statement D Codeforces Round 746 (Div. 2) {1592} PROGRAMMING 2000.0 95583
1270 Hidden Fortress interactive math Statement H Bubble Cup 14 - Finals Online Mirror (Unrated, ICPC Rules, Teams Preferred, Div. 1) {1599} PROGRAMMING BubbleCup2021.pdf
5155 Too Many Impostors (easy version) constructive algorithms interactive Statement D1 Codeforces Round 761 (Div. 2) {1617} PROGRAMMING 2000.0 Editorial for Codeforces Round #761 (Div. 2)
2018 Too Many Impostors (hard version) constructive algorithms interactive Statement D2 Codeforces Round 761 (Div. 2) {1617} PROGRAMMING 1000.0 Editorial for Codeforces Round #761 (Div. 2)
7493 Hidden Permutations dfs and similar interactive math Statement C Hello 2022 {1621} PROGRAMMING 1500.0
3777 Interacdive Problem binary search constructive algorithms interactive Statement F Codeforces Round 764 (Div. 3) {1624} PROGRAMMING Codeforces Round #764 (Div. 3) Editorial
3569 Grid Xor constructive algorithms greedy implementation interactive math Statement C Codeforces Round 767 (Div. 1) {1628} PROGRAMMING 1250.0 99276
366 Perfect Matching data structures interactive trees Statement F Educational Codeforces Round 122 (Rated for Div. 2) {1633} PROGRAMMING 99539
4714 Finding Zero constructive algorithms greedy interactive Statement D Codeforces Round 770 (Div. 2) {1634} PROGRAMMING 2000.0 Codeforces Round #770 (Div. 2) editorial
0 Treasure Hunt graphs graphs graphs interactive interactive Statement D Pinely Treasure Hunt Contest {1639} PROGRAMMING
0 Treasure Hunt graphs graphs interactive interactive Statement C Pinely Treasure Hunt Contest {1639} PROGRAMMING
0 Treasure Hunt graphs interactive Statement A Pinely Treasure Hunt Contest {1639} PROGRAMMING
0 Treasure Hunt graphs interactive Statement B Pinely Treasure Hunt Contest {1639} PROGRAMMING
0 Treasure Hunt graphs interactive Statement E Pinely Treasure Hunt Contest {1639} PROGRAMMING
0 Treasure Hunt graphs interactive Statement F Pinely Treasure Hunt Contest {1639} PROGRAMMING
0 Treasure Hunt graphs interactive Statement G Pinely Treasure Hunt Contest {1639} PROGRAMMING
0 Treasure Hunt graphs interactive Statement H Pinely Treasure Hunt Contest {1639} PROGRAMMING
0 Treasure Hunt graphs interactive Statement I Pinely Treasure Hunt Contest {1639} PROGRAMMING
0 Treasure Hunt graphs interactive Statement J Pinely Treasure Hunt Contest {1639} PROGRAMMING
0 Treasure Hunt graphs interactive Statement K Pinely Treasure Hunt Contest {1639} PROGRAMMING
4625 GCD Guess bitmasks chinese remainder theorem constructive algorithms interactive math number theory Statement D Codeforces Round 781 (Div. 2) {1665} PROGRAMMING 1500.0 Codeforces Round #781 (Div. 2) Editorial
1767 Interactive Treasure Hunt brute force interactive math Statement I 2021-2022 ICPC, NERC, Northern Eurasia Onsite (Unrated, Online Mirror, ICPC Rules, Teams Preferred) {1666} PROGRAMMING Tutorial (PDF)
2514 notepad.exe binary search constructive algorithms greedy interactive Statement E Codeforces Global Round 20 {1672} PROGRAMMING 1500.0 Global Round 20 Editorial 2200
954 Anti-Theft Road Planning bitmasks constructive algorithms divide and conquer greedy interactive math Statement F Codeforces Round 785 (Div. 2) {1673} PROGRAMMING 3250.0 Codeforces Round #785 (Div. 2) Editorial
4131 Railway System constructive algorithms dsu graphs greedy interactive sortings Statement B Codeforces Round 796 (Div. 1) {1687} PROGRAMMING 750.0 Editorial of Codeforces Round 796
4982 Guess The String binary search brute force constructive algorithms dsu interactive Statement D Educational Codeforces Round 130 (Rated for Div. 2) {1697} PROGRAMMING 103835
12020 Fixed Point Guessing binary search constructive algorithms interactive Statement D Codeforces Round 803 (Div. 2) {1698} PROGRAMMING 1500.0 Codeforces Round #803 (Div. 2) Editorial
692 Mark and the Online Exam bitmasks constructive algorithms interactive math probabilities Statement F Codeforces Round 807 (Div. 2) {1705} PROGRAMMING 3000.0 Codeforces Round #807 (Div 2.) Editorial
6219 Tournament Countdown constructive algorithms fft greedy greedy interactive number theory probabilities Statement D Codeforces Round 812 (Div. 2) {1713} PROGRAMMING 2000.0 Codeforces Round #812 (Div. 2) Editorial 1800
588 Crop Squares constructive algorithms geometry interactive math Statement F Codeforces Round 816 (Div. 2) {1715} PROGRAMMING 3000.0 Codeforces Round #816 (Div. 2) editorial
513 Matching Reduction graph matchings interactive Statement F Educational Codeforces Round 134 (Rated for Div. 2) {1721} PROGRAMMING 106416
7899 Guess the Cycle Size interactive probabilities Statement E Codeforces Round 820 (Div. 3) {1729} PROGRAMMING Codeforces Round #820 (Div. 3) Editorial
1373 Connectivity Addicts constructive algorithms dsu graphs greedy interactive shortest paths sortings trees Statement F Codeforces Global Round 22 {1738} PROGRAMMING 2750.0 Editorial of Codeforces Global Round <strong>22</strong>
1688 Joking (Easy Version) binary search bitmasks constructive algorithms interactive ternary search Statement E1 Codeforces Global Round 23 {1746} PROGRAMMING 2000.0 Codeforces Global Round 23 Editorial
483 Joking (Hard Version) dp interactive Statement E2 Codeforces Global Round 23 {1746} PROGRAMMING 1750.0 Codeforces Global Round 23 Editorial
155 Centroid Guess interactive probabilities trees Statement G Pinely Round 1 (Div. 1 + Div. 2) {1761} PROGRAMMING 3500.0 Pinely Round 1 (Div. 1 + Div. 2) Editorial
4314 GCD Queries interactive number theory Statement D Codeforces Round 838 (Div. 2) {1762} PROGRAMMING 2000.0 Codeforces Round #838 (Div. 2) Editorial
697 Doremy's Perfect DS Class (Easy Version) binary search interactive Statement G1 Codeforces Global Round 24 {1764} PROGRAMMING 2000.0 Codeforces Global Round 24 Editorial
636 Doremy's Perfect DS Class (Medium Version) binary search interactive Statement G2 Codeforces Global Round 24 {1764} PROGRAMMING 500.0 Codeforces Global Round 24 Editorial
558 Doremy's Perfect DS Class (Hard Version) binary search interactive Statement G3 Codeforces Global Round 24 {1764} PROGRAMMING 500.0 Codeforces Global Round 24 Editorial
477 Guess the String interactive Statement G 2022-2023 ICPC, NERC, Southern and Volga Russian Regional Contest (Online Mirror, ICPC Rules, Preferably Teams) {1765} PROGRAMMING 109642 2600
577 Interactive Factorial Guessing brute force games implementation interactive Statement I 2022-2023 ICPC, NERC, Northern Eurasia Onsite (Unrated, Online Mirror, ICPC Rules, Teams Preferred) {1773} PROGRAMMING 2500
486 Hot and Cold binary search interactive Statement H 2022-2023 ICPC, NERC, Northern Eurasia Onsite (Unrated, Online Mirror, ICPC Rules, Teams Preferred) {1773} PROGRAMMING 2600
892 Spinach Pizza games geometry greedy interactive Statement I SWERC 2022-2023 - Online Mirror (Unrated, ICPC Rules, Teams Preferred) {1776} PROGRAMMING
981 Library game games greedy interactive sortings Statement C SWERC 2022-2023 - Online Mirror (Unrated, ICPC Rules, Teams Preferred) {1776} PROGRAMMING
2025 Anya's Simultaneous Exhibition constructive algorithms data structures graphs greedy interactive sortings Statement E Hello 2023 {1779} PROGRAMMING 2250.0
5814 Bit Guessing Game binary search bitmasks interactive Statement D Codeforces Round 846 (Div. 2) {1780} PROGRAMMING 1500.0 111841
8903 Li Hua and Chess brute force constructive algorithms greedy hashing interactive Statement C Codeforces Round 864 (Div. 2) {1797} PROGRAMMING 1500.0 Codeforces Round 864 (Div. 2) Editorial
16582 Interview binary search implementation interactive Statement E Codeforces Round 859 (Div. 4) {1807} PROGRAMMING 114143
171 Expected Twist *special interactive Statement H April Fools Day Contest 2023 {1812} PROGRAMMING Editorial of April Fools Day Contest 2023
6286 Unmysterious Language *special interactive strings Statement J April Fools Day Contest 2023 {1812} PROGRAMMING Editorial of April Fools Day Contest 2023
3593 Sum Graph constructive algorithms graphs implementation interactive math shortest paths trees Statement B Codeforces Round 865 (Div. 1) {1815} PROGRAMMING 1250.0 Editorial of Codeforces Round #865 2000
379 Roads in E City interactive math probabilities trees Statement E Codeforces Round 866 (Div. 1) {1819} PROGRAMMING 2750.0 Codeforces Round #866 (Div.1, Div.2, based on Lipetsk Team Olympiad) Editorial
456 Fading into Fog geometry interactive math probabilities Statement F Codeforces Round 870 (Div. 2) {1826} PROGRAMMING 3000.0 Codeforces Round #870 (Div. 2) Editorial 2800
379 Stuck Conveyor binary search interactive Statement F Codeforces Round 877 (Div. 2) {1838} PROGRAMMING 3000.0 Codeforces Round #877 (Div. 2) Editorial
1533 Decreasing Game constructive algorithms dp greedy interactive Statement E Codeforces Round 876 (Div. 2) {1839} PROGRAMMING 2750.0 Codeforces Round #876 (Div. 2) Editorial
2781 In Search of Truth (Easy Version) brute force constructive algorithms interactive math probabilities Statement G1 Codeforces Round 878 (Div. 3) {1840} PROGRAMMING Codeforces Round #878 (Div.3) Editorial
1180 In Search of Truth (Hard Version) constructive algorithms interactive math probabilities Statement G2 Codeforces Round 878 (Div. 3) {1840} PROGRAMMING Codeforces Round #878 (Div.3) Editorial
3709 Rudolph and Mimic constructive algorithms greedy implementation interactive Statement F Codeforces Round 883 (Div. 3) {1846} PROGRAMMING
371 Triangle Platinum? implementation interactive Statement E Codeforces Round 882 (Div. 2) {1847} PROGRAMMING 2750.0 Tutorial
651 Michael and Hotel interactive trees Statement D Codeforces Round 889 (Div. 1) {1854} PROGRAMMING 2000.0 Editorial of Codeforces Round 889 (Div. 1 + Div. 2)
3751 More Wrong divide and conquer interactive Statement D Codeforces Round 890 (Div. 2) supported by Constructor Institute {1856} PROGRAMMING 2000.0 Codeforces Round #890 (Div. 2) Editorial
1261 Rollbacks (Hard Version) bitmasks data structures interactive trees Statement E2 Codeforces Round 893 (Div. 2) {1858} PROGRAMMING 1000.0 Codeforces Round #893 (Div. 2) Editorial 2600
12654 Salyg1n and the MEX Game constructive algorithms data structures games greedy interactive Statement C Codeforces Round 897 (Div. 2) {1867} PROGRAMMING 1250.0
4323 Salyg1n and Array (simple version) constructive algorithms interactive math Statement E1 Codeforces Round 897 (Div. 2) {1867} PROGRAMMING 2000.0
3747 Salyg1n and Array (hard version) constructive algorithms interactive math Statement E2 Codeforces Round 897 (Div. 2) {1867} PROGRAMMING 1000.0
1565 Interactive Game with Coloring brute force constructive algorithms graphs implementation interactive math trees Statement E Educational Codeforces Round 155 (Rated for Div. 2) {1879} PROGRAMMING 120773 2400
492 Good Colorings binary search constructive algorithms graphs interactive Statement E Codeforces Round 905 (Div. 1) {1887} PROGRAMMING 2000.0 Codeforces Round #905 (Div. 1, Div. 2, Div. 3) Editorial
409 Pepe Racing constructive algorithms interactive sortings Statement G CodeTON Round 7 (Div. 1 + Div. 2, Rated, Prizes!) {1896} PROGRAMMING 3250.0 CodeTON Round 7 (Div. 1 + Div. 2, Rated, Prizes!) Editorial
2503 Geo Game constructive algorithms dp games greedy interactive math Statement E Codeforces Round 912 (Div. 2) {1903} PROGRAMMING 2250.0 Codeforces Round #912 (Div. 2) Editorial
269 Cursed Game interactive Statement C 2023-2024 ICPC, Asia Jakarta Regional Contest (Online Mirror, Unrated, ICPC Rules, Teams Preferred) {1906} PROGRAMMING problem_analysis.pdf
2053 ace5 and Task Order binary search divide and conquer implementation interactive probabilities sortings Statement E Codeforces Round 922 (Div. 2) {1918} PROGRAMMING 2500.0 Codeforces Round #922 (Div. 2) Editorial
178 Tree Diameter interactive trees Statement H Hello 2024 {1919} PROGRAMMING 5000.0 3500
225 Anti-Proxy Attendance constructive algorithms interactive ternary search Statement F Codeforces Round 921 (Div. 1) {1924} PROGRAMMING 3000.0 Codeforces Round 921 (Div. 1, Div. 2) Editorial
362 Interactive Mex Tree interactive Statement H think-cell Round 1 {1930} PROGRAMMING 3500.0 think-cell Round 1 Editorial
1748 XOR Break --- Game Version bitmasks games greedy interactive Statement D2 Codeforces Round 931 (Div. 2) {1934} PROGRAMMING 1250.0 Tutorial
8057 Find a Mine constructive algorithms geometry greedy interactive math Statement C Codeforces Round 931 (Div. 2) {1934} PROGRAMMING 1500.0 Tutorial
8637 Bitwise Operation Wizard bitmasks constructive algorithms greedy interactive math Statement A Codeforces Round 930 (Div. 1) {1936} PROGRAMMING 500.0 Codeforces Round 930 (Div. 1, Div. 2) Editorial
30 Draw Polygon Lines *special constructive algorithms dp geometry interactive Statement A XVIII Open Olympiad in Informatics - Final Stage, Day 1 (Unrated, Online Mirror, IOI rules) {1939} PROGRAMMING
937 Arithmancy (Easy) brute force constructive algorithms interactive strings Statement D1 Helvetic Coding Contest 2024 online mirror (teams allowed, unrated) {1970} PROGRAMMING Helvetic Coding Contest 2024 Editorial 2100
308 Arithmancy (Medium) constructive algorithms interactive probabilities strings Statement D2 Helvetic Coding Contest 2024 online mirror (teams allowed, unrated) {1970} PROGRAMMING Helvetic Coding Contest 2024 Editorial 2600
160 Arithmancy (Hard) interactive Statement D3 Helvetic Coding Contest 2024 online mirror (teams allowed, unrated) {1970} PROGRAMMING Helvetic Coding Contest 2024 Editorial 3100
2245 Cat, Fox and Maximum Array Split brute force interactive math Statement D Codeforces Round 945 (Div. 2) {1973} PROGRAMMING 2000.0 Editorial for Codeforces Round #945 (Div. 2) 2400
933 Tensor constructive algorithms graphs interactive Statement E Codeforces Round 948 (Div. 2) {1977} PROGRAMMING 2500.0 129858 2600
436 Kostyanych's Theorem brute force graphs interactive Statement F Codeforces Round 951 (Div. 2) {1979} PROGRAMMING 3000.0 Codeforces Round 951 (Div. 2) Editorial
140 Fumo Temple interactive Statement H EPIC Institute of Technology Round Summer 2024 (Div. 1 + Div. 2) {1987} PROGRAMMING 5000.0 EPIC Institute of Technology Round Summer 2024 (Div. 1 + Div. 2) Editorial
1135 Catch the Mole(Easy Version) binary search constructive algorithms data structures interactive trees Statement E1 Codeforces Round 960 (Div. 2) {1990} PROGRAMMING 2000.0 Video Tutorial
1098 Catch the Mole(Hard Version) binary search data structures dfs and similar interactive trees Statement E2 Codeforces Round 960 (Div. 2) {1990} PROGRAMMING 750.0 Video Tutorial
5101 Coloring Game constructive algorithms games graphs greedy interactive Statement E Pinely Round 4 (Div. 1 + Div. 2) {1991} PROGRAMMING 2000.0 Video Tutorial
171 Grid Game constructive algorithms games greedy interactive Statement I Pinely Round 4 (Div. 1 + Div. 2) {1991} PROGRAMMING 4000.0 Video Tutorial
772 Fortnite interactive math Statement H Codeforces Round 959 sponsored by NEAR (Div. 1 + Div. 2) {1994} PROGRAMMING 3750.0 Video Tutorial
14443 Ruler (easy version) binary search interactive ternary search Statement G1 Codeforces Round 964 (Div. 4) {1999} PROGRAMMING Video Tutorial
10934 Ruler (hard version) binary search interactive ternary search Statement G2 Codeforces Round 964 (Div. 4) {1999} PROGRAMMING Video Tutorial
12741 Guess The Tree binary search brute force greedy interactive trees Statement C Codeforces Round 967 (Div. 2) {2001} PROGRAMMING 1500.0 Video Tutorial
14481 Password Cracking brute force constructive algorithms interactive strings Statement C Codeforces Round 973 (Div. 2) {2013} PROGRAMMING 1250.0 134298
3984 Asesino (Easy Version) binary search constructive algorithms implementation interactive Statement D1 Codeforces Round 978 (Div. 2) {2022} PROGRAMMING 1750.0 Codeforces Round 978 (Div 2) Editorial
823 Asesino (Hard Version) interactive Statement D2 Codeforces Round 978 (Div. 2) {2022} PROGRAMMING 2000.0 Codeforces Round 978 (Div 2) Editorial
449 Penchick and Even Medians binary search constructive algorithms interactive Statement F Codeforces Round 987 (Div. 2) {2031} PROGRAMMING 3000.0 Codeforces Round 987 (Div. 2) Editorial
6175 Genokraken binary search constructive algorithms data structures graphs interactive trees two pointers Statement D Codeforces Round 983 (Div. 2) {2032} PROGRAMMING 1750.0 Codeforces Round 983 (Div. 2) Editorial
1660 Library of Magic binary search bitmasks constructive algorithms interactive Statement G Codeforces Round 984 (Div. 3) {2036} PROGRAMMING Codeforces Round 984 (Div. 3) Editorial
7349 Kachina's Favorite Binary String greedy interactive two pointers Statement E Codeforces Round 988 (Div. 3) {2037} PROGRAMMING Video Tutorial
2944 Guess One Character constructive algorithms interactive Statement G 2024-2025 ICPC, NERC, Southern and Volga Russian Regional Contest (Unrated, Online Mirror, ICPC Rules, Preferably Teams) {2038} PROGRAMMING 1900
1582 Broken Queries binary search bitmasks interactive Statement E Codeforces Round 994 (Div. 2) {2049} PROGRAMMING 2250.0 Codeforces Round #994 (Div. 2) Editorial
68 Hunting Hoglins in Hogwarts interactive Statement H 2024-2025 ICPC, NERC, Northern Eurasia Finals (Unrated, Online Mirror, ICPC Rules, Teams Preferred) {2052} PROGRAMMING
717 Secret Message constructive algorithms math Statement G Hello 2025 {2057} PROGRAMMING 3750.0
489 Kevin and Teams constructive algorithms graphs interactive Statement G IAEPC Preliminary Contest (Codeforces Round 999, Div. 1 + Div. 2) {2061} PROGRAMMING 3000.0 IAEPC Preliminary Contest (Codeforces Round 999, Div. 1 + Div. 2) Editorial
7121 Object Identification graphs implementation interactive Statement A Codeforces Round 1004 (Div. 1) {2066} PROGRAMMING 750.0 139415
76 Minus Operator interactive Statement E 2025 ICPC Asia Pacific Championship - Online Mirror (Unrated, Online Mirror, ICPC Rules, Teams Preferred) {2073} PROGRAMMING
370 Secret Lilies and Roses interactive Statement H 2025 ICPC Asia Pacific Championship - Online Mirror (Unrated, Online Mirror, ICPC Rules, Teams Preferred) {2073} PROGRAMMING
6623 Empty Triangle geometry interactive probabilities Statement E Codeforces Round 1009 (Div. 3) {2074} PROGRAMMING Codeforces Round 1009 (Div. 3) — Editorial
3642 Finding OR Sum bitmasks constructive algorithms implementation interactive math Statement B Codeforces Round 1008 (Div. 1) {2077} PROGRAMMING 1000.0 Codeforces Round 1008 (Div. 1, Div. 2) Editorial
142 Online Palindrome brute force constructive algorithms interactive Statement F Educational Codeforces Round 177 (Rated for Div. 2) {2086} PROGRAMMING Educational Codeforces Round 177 Editorial
267 Uppercase or Lowercase? *special *special interactive Statement D Kotlin Heroes: Episode 12 {2087} PROGRAMMING 141608