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
Solved |
Name |
Tags |
Solutions |
Index |
Contest |
Type |
Points |
Tutorial |
Rating Level |
|---|---|---|---|---|---|---|---|---|---|
| 16026 | Bear and Prime 100 | constructive algorithms interactive math | Statement | A | Codeforces Round 356 (Div. 1) {679} | PROGRAMMING | Codeforces Round #356 — Editorial | 1400 | |
| 9277 | 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 | |
| 655 | New Year and Finding Roots | constructive algorithms implementation interactive trees | Statement | F | Good Bye 2016 {750} | PROGRAMMING | Good Bye 2016 — hints and codes | 2700 | |
| 15494 | 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 | |
| 227 | 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 | |
| 2647 | Interactive LowerBound | brute force interactive probabilities | Statement | B | AIM Tech Round 4 (Div. 1) {843} | PROGRAMMING | AIM Tech Round 4 -- Editorial | 2000 | |
| 1326 | 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 | |
| 600 | 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 | |||
| 2271 | 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 | |
| 2664 | 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 | |
| 2619 | Subway Pursuit | binary search interactive probabilities | Statement | B | Codeforces Round 507 (Div. 1, based on Olympiad of Metropolises) {1039} | PROGRAMMING | 61668 | 2100 | |
| 1722 | 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 | |
| 2594 | Pick Heroes | greedy implementation interactive sortings | Statement | C | Mail.Ru Cup 2018 Round 3 {1056} | PROGRAMMING | Mail.Ru Cup 2018 Round 3 Editorial | 1700 | |
| 973 | Lost Root | interactive probabilities | Statement | F | Codeforces Round 523 (Div. 2) {1061} | PROGRAMMING | Tutorial (en) | 2400 | |
| 1004 | Katya and Segments Sets | data structures interactive sortings | Statement | F | Codeforces Round 524 (Div. 2) {1080} | PROGRAMMING | Codeforces Round #524 (Div. 2) Editorial | 2700 | |
| 257 | New Year and the Factorisation Collaboration | interactive math number theory | Statement | G | Good Bye 2018 {1091} | PROGRAMMING | Editorial | 3100 | |
| 3272 | Arithmetic Progression | binary search interactive number theory probabilities | Statement | E | Codeforces Round 538 (Div. 2) {1114} | PROGRAMMING | Codeforces Round #538 (Div. 2) Editorial | 2100 | |
| 1669 | 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 | |
| 673 | Legendary Tree | binary search interactive trees | Statement | E | Codeforces Round 542 [Alex Lopashev Thanks-Round] (Div. 1) {1129} | PROGRAMMING | 65520 | 3000 | |
| 2258 | Cooperative Game | constructive algorithms interactive number theory | Statement | D | Codeforces Round 545 (Div. 1) {1137} | PROGRAMMING | Codeforces Round #545 – Editorial | 2500 | |
| 1703 | Guess the Root | brute force interactive math | Statement | E | Educational Codeforces Round 63 (Rated for Div. 2) {1155} | PROGRAMMING | 66687 | 2200 | |
| 232 | Strange device | binary search interactive math trees | Statement | E | Codeforces Round 559 (Div. 1) {1158} | PROGRAMMING | 66993 | 3300 | |
| 17438 | Lost Numbers | brute force divide and conquer interactive math | Statement | B | Educational Codeforces Round 65 (Rated for Div. 2) {1167} | PROGRAMMING | 67058 | 1400 | |
| 2067 | 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 | |
| 237 | Knightmare (easy) | graphs interactive shortest paths | Statement | E1 | Codeforces Round 577 (Div. 2) {1201} | PROGRAMMING | Codeforces Round #577 (Div 2) Editorial | 2900 | |
| 174 | Knightmare (hard) | graphs interactive shortest paths | Statement | E2 | Codeforces Round 577 (Div. 2) {1201} | PROGRAMMING | Codeforces Round #577 (Div 2) Editorial | 3000 | |
| 6786 | XOR Guessing | bitmasks interactive math | Statement | E | Educational Codeforces Round 71 (Rated for Div. 2) {1207} | PROGRAMMING | Educational Codeforces Round 71 Editorial | 1800 | |
| 1816 | Point Ordering | constructive algorithms geometry interactive math | Statement | C | Codeforces Round 601 (Div. 1) {1254} | PROGRAMMING | Codeforces Round #601 Editorial | 2300 | |
| 1074 | 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 | |
| 5001 | Strange Device | constructive algorithms interactive math sortings | Statement | D | Good Bye 2019 {1270} | PROGRAMMING | Разбор Goodbye 2019 | 1900 | |
| 2481 | Enchanted Artifact | constructive algorithms interactive strings | Statement | D | Codeforces Round 610 (Div. 2) {1282} | PROGRAMMING | 72461 | 2300 | |
| 1628 | Madhouse (Easy version) | brute force constructive algorithms interactive math | Statement | C1 | Codeforces Round 612 (Div. 1) {1286} | PROGRAMMING | Codeforces Round #612 - Editorial | 2400 | |
| 773 | Madhouse (Hard version) | brute force constructive algorithms hashing interactive math | Statement | C2 | Codeforces Round 612 (Div. 1) {1286} | PROGRAMMING | Codeforces Round #612 - Editorial | 2900 | |
| 480 | 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 |
| 269 | So Mean | interactive math | Statement | E | Codeforces Round 618 (Div. 1) {1299} | PROGRAMMING | 2250.0 | Codeforces Round #618 Editorial | 3400 |
| 5411 | 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 |
| 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 | |
| 1008 | Find a Gift | binary search interactive probabilities | Statement | G | Educational Codeforces Round 87 (Rated for Div. 2) {1354} | PROGRAMMING | 77593 | 2600 | |
| 985 | 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 |
| 4476 | Guess The Maximums | binary search divide and conquer implementation interactive math | Statement | D | Codeforces Round 646 (Div. 2) {1363} | PROGRAMMING | 2000.0 | 78202 | 2100 |
| 1683 | X-OR | bitmasks constructive algorithms interactive probabilities | Statement | E | Codeforces Round 649 (Div. 2) {1364} | PROGRAMMING | 2500.0 | Codeforces round #649 editorial | 2700 |
| 1557 | Secure Password | bitmasks combinatorics constructive algorithms interactive math | Statement | G | Codeforces Round 648 (Div. 2) {1365} | PROGRAMMING | 3000.0 | Editorial — Codeforces Round #648 | 2800 |
| 1134 | Lamps on a Circle | games greedy implementation interactive math | Statement | F | Codeforces Global Round 8 {1368} | PROGRAMMING | 3000.0 | Codeforces Global Round 8: editorial | |
| 1850 | 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 | |
| 1741 | 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 | |
| 2573 | Integer Game | brute force constructive algorithms games interactive math | Statement | F | Codeforces Global Round 9 {1375} | PROGRAMMING | 2000.0 | 79731 | |
| 3907 | Omkar and Duck | bitmasks constructive algorithms interactive math | Statement | E | Codeforces Global Round 10 {1392} | PROGRAMMING | 2000.0 | Codeforces Global Round 10 — Editorial | |
| 362 | 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 | ||
| 1311 | 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 | |
| 1968 | 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 | |
| 15337 | Chocolate Bunny | constructive algorithms interactive math two pointers | Statement | C | Codeforces Round 669 (Div. 2) {1407} | PROGRAMMING | 1500.0 | Codeforces Round #669 Editorial | |
| 815 | Olha and Igor | interactive trees | Statement | F | Codeforces Round 682 (Div. 2) {1438} | PROGRAMMING | 3000.0 | Codeforces Round #682 (Div. 2) Editorial | |
| 172 | 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 | |
| 5596 | Bitwise Queries (Easy Version) | bitmasks constructive algorithms interactive math | Statement | E1 | Codeforces Round 685 (Div. 2) {1451} | PROGRAMMING | 1500.0 | Editorial — Codeforces Round #685 | |
| 3966 | Bitwise Queries (Hard Version) | bitmasks constructive algorithms interactive math | Statement | E2 | Codeforces Round 685 (Div. 2) {1451} | PROGRAMMING | 1000.0 | Editorial — Codeforces Round #685 | |
| 1477 | Strange Shuffle | binary search brute force constructive algorithms interactive probabilities | Statement | C | Codeforces Round 694 (Div. 1) {1470} | PROGRAMMING | 1000.0 | 86464 | |
| 13382 | Searching Local Minimum | binary search interactive ternary search | Statement | A | Codeforces Round 700 (Div. 1) {1479} | PROGRAMMING | 500.0 | Editorial of Codeforces Round #700 | |
| 527 | Enchanted Matrix | bitmasks interactive number theory | Statement | F | Codeforces Round 705 (Div. 2) {1493} | PROGRAMMING | 3250.0 | Codeforces Round #705 (Div.2) Editorial | |
| 2184 | 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 | |
| 599 | 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 | ||
| 715 | 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 | |
| 403 | Median Queries | constructive algorithms interactive probabilities | Statement | F | Codeforces Round 723 (Div. 2) {1526} | PROGRAMMING | 3500.0 | Codeforces Round #723 (Div. 2) Editorial | |
| 2113 | 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 | |
| 6984 | 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 | |
| 418 | 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 | |
| 3151 | Gold Transfer | binary search data structures greedy interactive trees | Statement | E | Educational Codeforces Round 110 (Rated for Div. 2) {1535} | PROGRAMMING | 91481 | ||
| 8067 | 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 | |
| 2204 | 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 | |
| 801 | AquaMoon and Wrong Coordinate | constructive algorithms interactive math | Statement | D | Codeforces Round 732 (Div. 1) {1545} | PROGRAMMING | 2250.0 | Codeforces Round #732 Editorial | 3000 |
| 471 | Guess the Perimeter | binary search interactive number theory | Statement | H | Codeforces Global Round 15 {1552} | PROGRAMMING | 2750.0 | Editorial of Global Round 15 | |
| 9011 | 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 |
| 796 | Assiut Chess | brute force interactive probabilities two pointers | Statement | E | Codeforces Round 737 (Div. 2) {1557} | PROGRAMMING | 3000.0 | Codeforces Round #737 Editorial | |
| 479 | 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) | |
| 184 | Xor-quiz | constructive algorithms dp interactive math number theory | Statement | H | Codeforces Global Round 16 {1566} | PROGRAMMING | 3750.0 | Codeforces Global Round 16 Editorial | |
| 545 | The Mind | constructive algorithms interactive probabilities | Statement | M | ICPC WF Moscow Invitational Contest - Online Mirror (Unrated, ICPC Rules, Teams Preferred) {1578} | PROGRAMMING | Tutorial (PDF) | ||
| 4046 | 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 |
| 2662 | 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 | |
| 1311 | Hidden Fortress | interactive math | Statement | H | Bubble Cup 14 - Finals Online Mirror (Unrated, ICPC Rules, Teams Preferred, Div. 1) {1599} | PROGRAMMING | BubbleCup2021.pdf | ||
| 7566 | Hidden Permutations | dfs and similar interactive math | Statement | C | Hello 2022 {1621} | PROGRAMMING | 1500.0 | ||
| 3677 | Grid Xor | constructive algorithms greedy implementation interactive math | Statement | C | Codeforces Round 767 (Div. 1) {1628} | PROGRAMMING | 1250.0 | 99276 | |
| 736 | Perfect Matching | data structures interactive trees | Statement | F | Educational Codeforces Round 122 (Rated for Div. 2) {1633} | PROGRAMMING | 99539 | ||
| 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 | |||
| 4773 | 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 | |
| 1789 | 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) | ||
| 983 | 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 | |
| 4203 | 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 | |
| 721 | 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 | |
| 6314 | 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 |
| 604 | Crop Squares | constructive algorithms geometry interactive math | Statement | F | Codeforces Round 816 (Div. 2) {1715} | PROGRAMMING | 3000.0 | Codeforces Round #816 (Div. 2) editorial | |
| 8086 | Guess the Cycle Size | interactive probabilities | Statement | E | Codeforces Round 820 (Div. 3) {1729} | PROGRAMMING | Codeforces Round #820 (Div. 3) Editorial | ||
| 1418 | 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> | |
| 1833 | 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 | |
| 156 | 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 | |
| 4571 | GCD Queries | interactive number theory | Statement | D | Codeforces Round 838 (Div. 2) {1762} | PROGRAMMING | 2000.0 | Codeforces Round #838 (Div. 2) Editorial | |
| 1000 | Library game | games greedy interactive sortings | Statement | C | SWERC 2022-2023 - Online Mirror (Unrated, ICPC Rules, Teams Preferred) {1776} | PROGRAMMING | |||
| 2094 | Anya's Simultaneous Exhibition | constructive algorithms data structures graphs greedy interactive sortings | Statement | E | Hello 2023 {1779} | PROGRAMMING | 2250.0 | ||
| 6314 | Unmysterious Language | *special interactive strings | Statement | J | April Fools Day Contest 2023 {1812} | PROGRAMMING | Editorial of April Fools Day Contest 2023 | ||
| 3687 | 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 |
| 386 | 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 | |
| 479 | 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 |
| 2861 | 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 | ||
| 1222 | 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 | ||
| 701 | 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) | |
| 1304 | 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 |
| 4412 | Salyg1n and Array (simple version) | constructive algorithms interactive math | Statement | E1 | Codeforces Round 897 (Div. 2) {1867} | PROGRAMMING | 2000.0 | ||
| 3814 | Salyg1n and Array (hard version) | constructive algorithms interactive math | Statement | E2 | Codeforces Round 897 (Div. 2) {1867} | PROGRAMMING | 1000.0 | ||
| 1614 | 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 | |
| 461 | 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 | |
| 2605 | 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 | |
| 2203 | 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 | |
| 185 | Tree Diameter | interactive trees | Statement | H | Hello 2024 {1919} | PROGRAMMING | 5000.0 | 3500 | |
| 239 | 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 | |
| 8263 | Find a Mine | constructive algorithms geometry greedy interactive math | Statement | C | Codeforces Round 931 (Div. 2) {1934} | PROGRAMMING | 1500.0 | Tutorial | |
| 8782 | 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 | |
| 972 | 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 | |
| 338 | 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 | |
| 2335 | 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 |
| 1235 | 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 | |
| 1212 | 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 | |
| 781 | Fortnite | interactive math | Statement | H | Codeforces Round 959 sponsored by NEAR (Div. 1 + Div. 2) {1994} | PROGRAMMING | 3750.0 | Video Tutorial | |
| 15069 | Ruler (easy version) | binary search interactive ternary search | Statement | G1 | Codeforces Round 964 (Div. 4) {1999} | PROGRAMMING | Video Tutorial | ||
| 11580 | Ruler (hard version) | binary search interactive ternary search | Statement | G2 | Codeforces Round 964 (Div. 4) {1999} | PROGRAMMING | Video Tutorial | ||
| 13103 | Guess The Tree | binary search brute force greedy interactive trees | Statement | C | Codeforces Round 967 (Div. 2) {2001} | PROGRAMMING | 1500.0 | Video Tutorial | |
| 14904 | Password Cracking | brute force constructive algorithms interactive strings | Statement | C | Codeforces Round 973 (Div. 2) {2013} | PROGRAMMING | 1250.0 | 134298 | |
| 6355 | 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 | |
| 7631 | Kachina's Favorite Binary String | greedy interactive two pointers | Statement | E | Codeforces Round 988 (Div. 3) {2037} | PROGRAMMING | Video Tutorial | ||
| 6864 | Empty Triangle | geometry interactive probabilities | Statement | E | Codeforces Round 1009 (Div. 3) {2074} | PROGRAMMING | Codeforces Round 1009 (Div. 3) — Editorial | ||
| 3754 | 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 | |
| 652 | Baudelaire (hard version) | binary search dfs and similar divide and conquer implementation interactive trees | Statement | G2 | Codeforces Round 1020 (Div. 3) {2106} | PROGRAMMING | Codeforces Round 1020 (Div. 3) Editorial | ||
| 1673 | Baudelaire (easy version) | binary search interactive trees | Statement | G1 | Codeforces Round 1020 (Div. 3) {2106} | PROGRAMMING | Codeforces Round 1020 (Div. 3) Editorial | ||
| 2465 | Needle in a Numstack | binary search brute force interactive math | Statement | D | Codeforces Round 1022 (Div. 2) {2108} | PROGRAMMING | 2250.0 | Codeforces Round 1022 Editorial | |
| 11826 | Hacking Numbers (Easy Version) | bitmasks constructive algorithms interactive math number theory | Statement | C1 | Codeforces Round 1025 (Div. 2) {2109} | PROGRAMMING | 1250.0 | Codeforces Round 1025 (Div. 2) Editorial | |
| 8944 | Hacking Numbers (Medium Version) | constructive algorithms interactive math number theory | Statement | C2 | Codeforces Round 1025 (Div. 2) {2109} | PROGRAMMING | 750.0 | Codeforces Round 1025 (Div. 2) Editorial | |
| 3346 | Hacking Numbers (Hard Version) | constructive algorithms interactive math number theory | Statement | C3 | Codeforces Round 1025 (Div. 2) {2109} | PROGRAMMING | 500.0 | Codeforces Round 1025 (Div. 2) Editorial | |
| 143 | Inter Active (Hard Version) | binary search bitmasks constructive algorithms graphs implementation interactive math probabilities | Statement | G2 | Atto Round 1 (Codeforces Round 1041, Div. 1 + Div. 2) {2127} | PROGRAMMING | 2750.0 | Atto Round 1 (Codeforces Round 1041, Div. 1 + Div. 2) Editorial | |
| 167 | Inter Active (Easy Version) | binary search constructive algorithms interactive interactive | Statement | G1 | Atto Round 1 (Codeforces Round 1041, Div. 1 + Div. 2) {2127} | PROGRAMMING | 2750.0 | Atto Round 1 (Codeforces Round 1041, Div. 1 + Div. 2) Editorial | |
| 108 | Top-K Tracker (Hard Version) | interactive interactive | Statement | F2 | Codeforces Round 1040 (Div. 1) {2129} | PROGRAMMING | 2500.0 | Codeforces Round 1040 (Div. 1, Div. 2) Editorial | |
| 1421 | From the Unknown (Hard Version) | binary search brute force constructive algorithms interactive math | Statement | D2 | Codeforces Round 1046 (Div. 1) {2135} | PROGRAMMING | 1250.0 | Codeforces Round 1046 (Div. 1, Div. 2) Editorial | |
| 9261 | For the Champion | constructive algorithms interactive math | Statement | B | Codeforces Round 1046 (Div. 1) {2135} | PROGRAMMING | 1000.0 | Codeforces Round 1046 (Div. 1, Div. 2) Editorial | |
| 4138 | From the Unknown (Easy Version) | constructive algorithms interactive math | Statement | D1 | Codeforces Round 1046 (Div. 1) {2135} | PROGRAMMING | 1250.0 | Codeforces Round 1046 (Div. 1, Div. 2) Editorial | |
| 772 | Hidden Single (Version 2) | divide and conquer interactive math probabilities | Statement | E2 | Codeforces Round 1053 (Div. 1) {2150} | PROGRAMMING | 1750.0 | Editorial of Codeforces Round 1053 (Div. 1, Div. 2) | |
| 2760 | Hidden Single (Version 1) | divide and conquer interactive math probabilities sortings | Statement | E1 | Codeforces Round 1053 (Div. 1) {2150} | PROGRAMMING | 2000.0 | Editorial of Codeforces Round 1053 (Div. 1, Div. 2) | |
| 4620 | Monotone Subsequence | brute force constructive algorithms dp graphs interactive math | Statement | E | Squarepoint Challenge (Codeforces Round 1055, Div. 1 + Div. 2) {2152} | PROGRAMMING | 3000.0 | Squarepoint Challenge (Codeforces Round 1055, Div. 1 + Div. 2) Editorial | |
| 6240 | Batteries | interactive math | Statement | D | Codeforces Round 1056 (Div. 2) {2155} | PROGRAMMING | 2000.0 | Codeforces Round 1056 (Div. 2) Editorial | |
| 5555 | Find the Last Number | bitmasks constructive algorithms interactive math | Statement | D | Codeforces Round 1061 (Div. 2) {2156} | PROGRAMMING | 2000.0 | Codeforces Round 1061 (Div. 2) Editorial | |
| 901 | Isaac's Queries | brute force constructive algorithms dfs and similar divide and conquer greedy interactive math probabilities | Statement | G | Codeforces Round 1066 (Div. 1 + Div. 2) {2157} | PROGRAMMING | 3000.0 | Codeforces Round 1066 (Div. 1 + Div. 2) Editorial | |
| 3589 | Encode and Decode (Hard Version) | bitmasks interactive math | Statement | A2 | Testing Round 20 (Unrated, Communication Problems) {2168} | PROGRAMMING | Testing Round 20 Editorial (officially unofficial) | ||
| 1628 | Shiro's Mirror Duel | interactive probabilities | Statement | E | Codeforces Round 1068 (Div. 2) {2173} | PROGRAMMING | 2250.0 | ||
| 111 | Game of Scientists (Version 2) | brute force chinese remainder theorem interactive math | Statement | E2 | Codeforces Round 1069 (Div. 1) {2174} | PROGRAMMING | 1750.0 | Codeforces Round 1069 Editorial | |
| 153 | Game of Scientists (Version 1) | chinese remainder theorem interactive math | Statement | E1 | Codeforces Round 1069 (Div. 1) {2174} | PROGRAMMING | 1750.0 | Codeforces Round 1069 Editorial | |
| 1281 | Blackslex and Penguin Migration | brute force interactive math | Statement | G | Codeforces Round 1071 (Div. 3) {2179} | PROGRAMMING | Codeforces Round 1071 (Div. 3) Editorial | ||
| 2925 | Blackslex and Another RGB Walking | graphs interactive number theory | Statement | F | Codeforces Round 1071 (Div. 3) {2179} | PROGRAMMING | Codeforces Round 1071 (Div. 3) Editorial | ||
| 172 | Cacti Classification | binary search interactive math | Statement | C | 2025-2026 ICPC, NERC, Northern Eurasia Finals (Unrated, Online Mirror, ICPC Rules, Teams Preferred) {2181} | PROGRAMMING | Tutorial | ||
| 1364 | Comparable Permutations | binary search greedy interactive sortings two pointers | Statement | C | Codeforces Round 1073 (Div. 1) {2190} | PROGRAMMING | 1750.0 | Codeforces Round 1073 (Div. 1, Div. 2) Editorial | |
| 2419 | Paths in a Tree | dfs and similar interactive sortings trees | Statement | G | Codeforces Round 1076 (Div. 3) {2193} | PROGRAMMING | Разбор Codeforces Round 1076 (Div. 3) | ||
| 61 | Bowser's Castle (Easy Version) | binary search constructive algorithms divide and conquer greedy interactive trees | Statement | H1 | Codeforces Round 1085 (Div. 1 + Div. 2) {2207} | PROGRAMMING | 3250.0 | Codeforces Round 1085 (Div. 1 + Div. 2) Editorial | |
| 53 | Bowser's Castle (Medium Version) | constructive algorithms divide and conquer interactive trees two pointers | Statement | H2 | Codeforces Round 1085 (Div. 1 + Div. 2) {2207} | PROGRAMMING | 1000.0 | Codeforces Round 1085 (Div. 1 + Div. 2) Editorial | |
| 71 | Bowser's Castle (Hard Version) | constructive algorithms divide and conquer interactive trees two pointers | Statement | H3 | Codeforces Round 1085 (Div. 1 + Div. 2) {2207} | PROGRAMMING | 1500.0 | Codeforces Round 1085 (Div. 1 + Div. 2) Editorial | |
| 375 | Binary Strings are Simple? | constructive algorithms dsu interactive number theory | Statement | E | Codeforces Round 1089 (Div. 2) {2210} | PROGRAMMING | 2750.0 | Codeforces Round 1089 (Div. 2) Editorial | |
| 1031 | Minimum Path Cover | dp interactive number theory trees | Statement | E | Nebius Round 2 (Codeforces Round 1088, Div. 1 + Div. 2) {2211} | PROGRAMMING | 2500.0 | Nebius Round 2 and Codeforces Round 1088 Editorial | |
| 855 | Oriented Journey | bitmasks communication constructive algorithms graphs hashing interactive trees | Statement | C | Codeforces Round 1092 (Unrated, Div. 1, Based on THUPC 2026 — Finals) {2215} | PROGRAMMING | 1750.0 | 152930 | |
| 3818 | Unique Values (Hard version) | binary search constructive algorithms divide and conquer interactive math | Statement | B2 | Codeforces Round 1093 (Div. 1) {2219} | PROGRAMMING | 500.0 | Codeforces Round 1093 (Div. 1, Div. 2) Editorial | |
| 442 | Send GCDs | communication interactive math | Statement | G | Order Capital Round 2 (Codeforces Round 1104, Div. 1 + Div. 2) {2237} | PROGRAMMING | 2750.0 | Order Capital Round 2 (Codeforces Round 1104, Div. 1 + Div. 2) Editorial | |
| 588 | lce4113 and Security Game | bitmasks interactive probabilities | Statement | E | Codeforces Round 1108 (Div. 2) {2246} | PROGRAMMING | 2250.0 | Codeforces Round 1108 (Div. 2) Editorial | |
| 1123 | Even If the World Turns | communication greedy interactive math number theory | Statement | C | Codeforces Round 1116 (Div. 1) {2255} | PROGRAMMING | 1750.0 |