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2065 Sasha and the Happy Tree Cutting bitmasks brute force dp fft graphs greedy trees Statement E Codeforces Round 926 (Div. 2) {1929} PROGRAMMING 2500.0 Codeforces Round #926 (Div. 2) Editorial.
935 Maximize the Difference bitmasks brute force dfs and similar Statement F think-cell Round 1 {1930} PROGRAMMING 2750.0 think-cell Round 1 Editorial
1177 Turtle Magic: Royal Turtle Shell Pattern bitmasks brute force combinatorics math Statement G Codeforces Round 929 (Div. 3) {1933} PROGRAMMING Codeforces Round 929 (Div. 3) Editorial
4127 XOR Break --- Solo Version bitmasks constructive algorithms greedy Statement D1 Codeforces Round 931 (Div. 2) {1934} PROGRAMMING 1500.0 Tutorial
1748 XOR Break --- Game Version bitmasks games greedy interactive Statement D2 Codeforces Round 931 (Div. 2) {1934} PROGRAMMING 1250.0 Tutorial
1645 Distance Learning Courses in MAC binary search bitmasks data structures greedy implementation math Statement E Codeforces Round 932 (Div. 2) {1935} PROGRAMMING 2500.0 Codeforces Round #932 (Div. 2) Editorial
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
622 Bitwise Paradox bitmasks data structures greedy two pointers Statement D Codeforces Round 930 (Div. 1) {1936} PROGRAMMING 2000.0 Codeforces Round 930 (Div. 1, Div. 2) Editorial
18132 Equal XOR bitmasks constructive algorithms Statement B Codeforces Round 934 (Div. 2) {1944} PROGRAMMING 1000.0 Codeforces Round #934 (Div1, Div2) Editorial
850 GCD is Greater bitmasks brute force number theory Statement H Codeforces Round 935 (Div. 3) {1945} PROGRAMMING 127377
5591 Birthday Gift bitmasks brute force constructive algorithms greedy implementation Statement D Codeforces Round 936 (Div. 2) {1946} PROGRAMMING 1750.0 Codeforces Round #936 (Div. 2) Editorial
872 MST with Matching bitmasks brute force trees Statement G Educational Codeforces Round 163 (Rated for Div. 2) {1948} PROGRAMMING Educational Codeforces Round 163 Editorial
6039 Shuffling Songs bitmasks dp graphs implementation strings Statement G Codeforces Round 937 (Div. 4) {1950} PROGRAMMING Codeforces Round 937 (Div. 4) Editorial
1514 The Most Reckless Defense bitmasks brute force constructive algorithms dp flows graph matchings Statement H Codeforces Round 938 (Div. 3) {1955} PROGRAMMING 128243
4753 Nene and the Mex Operator bitmasks brute force constructive algorithms divide and conquer dp greedy implementation Statement D Codeforces Round 939 (Div. 2) {1956} PROGRAMMING 1750.0 [Editorial] Codeforces Round 939 (Div. 2)
20360 A BIT of a Construction bitmasks constructive algorithms greedy implementation Statement B Codeforces Round 940 (Div. 2) and CodeCraft-23 {1957} PROGRAMMING 1000.0 Codeforces Round #940 and CodeCraft-23 (Div. 2) Editorial 1100
5775 A BIT of an Inequality bitmasks brute force dp math Statement D Codeforces Round 940 (Div. 2) and CodeCraft-23 {1957} PROGRAMMING 1750.0 Codeforces Round #940 and CodeCraft-23 (Div. 2) Editorial 1900
8085 Missing Subsequence Sum bitmasks constructive algorithms greedy number theory Statement B Codeforces Round 941 (Div. 1) {1965} PROGRAMMING 1250.0 Codeforces Round #941 (Div. 1, Div. 2) Editorial 1800
2227 Fenwick Tree bitmasks brute force combinatorics data structures dp math trees Statement C Codeforces Round 942 (Div. 1) {1967} PROGRAMMING 1250.0 Tutorial 2300
538 Min-Fund Prison (Hard) bitmasks dfs and similar dp graphs trees Statement G3 Helvetic Coding Contest 2024 online mirror (teams allowed, unrated) {1970} PROGRAMMING Helvetic Coding Contest 2024 Editorial 2400
16778 Cat, Fox and the Lonely Array binary search bitmasks data structures greedy math two pointers Statement B Codeforces Round 945 (Div. 2) {1973} PROGRAMMING 1000.0 Editorial for Codeforces Round #945 (Div. 2) 1300
319 Maximum GCD Sum Queries bitmasks brute force dp implementation number theory Statement F Codeforces Round 945 (Div. 2) {1973} PROGRAMMING 3000.0 Editorial for Codeforces Round #945 (Div. 2) 3100
1035 Set bitmasks brute force combinatorics dfs and similar divide and conquer dp math Statement F Codeforces Round 947 (Div. 1 + Div. 2) {1975} PROGRAMMING 2500.0 editorial_zh.pdf 2600
19862 Binary Colouring bitmasks constructive algorithms greedy math Statement B Codeforces Round 948 (Div. 2) {1977} PROGRAMMING 1250.0 129858 1100
2333 XORificator bitmasks brute force greedy hashing Statement D Codeforces Round 948 (Div. 2) {1977} PROGRAMMING 2000.0 129858 2300
7833 Fixing a Binary String bitmasks brute force constructive algorithms greedy hashing strings Statement D Codeforces Round 951 (Div. 2) {1979} PROGRAMMING 2000.0 Codeforces Round 951 (Div. 2) Editorial
26361 XOR Sequences bitmasks greedy Statement B Codeforces Round 951 (Div. 2) {1979} PROGRAMMING 1000.0 Codeforces Round 951 (Div. 2) Editorial
1689 Yasya and the Mysterious Tree bitmasks data structures dfs and similar graphs strings trees Statement G Codeforces Round 950 (Div. 3) {1980} PROGRAMMING 130135
6329 Turtle and an Incomplete Sequence bitmasks constructive algorithms greedy implementation math Statement C Codeforces Round 949 (Div. 2) {1981} PROGRAMMING 1500.0 Simplified Chinese Tutorial
16376 Turtle and an Infinite Sequence bitmasks math Statement B Codeforces Round 949 (Div. 2) {1981} PROGRAMMING 1000.0 Simplified Chinese Tutorial
1895 Number of k-good subarrays bitmasks combinatorics divide and conquer dp math meet-in-the-middle Statement E Codeforces Round 955 (Div. 2, with prizes from NEAR!) {1982} PROGRAMMING 2500.0 130839
1514 array-value binary search bitmasks data structures two pointers Statement F Codeforces Round 956 (Div. 2) and ByteRace 2024 {1983} PROGRAMMING 2500.0
283 Your Loss bitmasks brute force trees Statement G Codeforces Round 956 (Div. 2) and ByteRace 2024 {1983} PROGRAMMING 3000.0
12165 D-Function bitmasks combinatorics math number theory Statement G Codeforces Round 952 (Div. 4) {1985} PROGRAMMING Codeforces Round 952 (Div. 4) Editorial
20243 Increasing Sequence with Fixed OR bitmasks constructive algorithms greedy Statement C Codeforces Round 958 (Div. 2) {1988} PROGRAMMING 1000.0 Editorial of Codeforces Round 958 (Div. 2)
23267 Substring and Subsequence bitmasks brute force dp graphs greedy hashing strings trees Statement B Educational Codeforces Round 167 (Rated for Div. 2) {1989} PROGRAMMING Educational Codeforces Round 167 Editorial
7694 Grid Puzzle bitmasks dp greedy Statement D Codeforces Round 960 (Div. 2) {1990} PROGRAMMING 1750.0 Video Tutorial
7869 Prime XOR Coloring bitmasks constructive algorithms graphs greedy math number theory Statement D Pinely Round 4 (Div. 1 + Div. 2) {1991} PROGRAMMING 1500.0 Video Tutorial
18870 AND Reconstruction bitmasks constructive algorithms greedy Statement B Pinely Round 4 (Div. 1 + Div. 2) {1991} PROGRAMMING 500.0 Video Tutorial
725 Xor-Grid Problem bitmasks dp Statement E Codeforces Round 963 (Div. 2) {1993} PROGRAMMING 2750.0 Editorial of Codeforces Round 963 (Div. 2)
1617 Minecraft bitmasks brute force dp math Statement G Codeforces Round 959 sponsored by NEAR (Div. 1 + Div. 2) {1994} PROGRAMMING 2750.0 Video Tutorial
19429 Fun Game bitmasks constructive algorithms greedy math Statement B Codeforces Round 959 sponsored by NEAR (Div. 1 + Div. 2) {1994} PROGRAMMING 1000.0 Video Tutorial
5470 Wooden Game bitmasks greedy math trees Statement E Codeforces Round 959 sponsored by NEAR (Div. 1 + Div. 2) {1994} PROGRAMMING 2000.0 Video Tutorial
396 Let Me Teach You a Lesson (Hard Version) 2-sat bitmasks data structures dp graphs matrices two pointers Statement E2 Codeforces Round 961 (Div. 2) {1995} PROGRAMMING 1500.0 Video Tutorial
2877 Cases bitmasks brute force combinatorics dfs and similar dp graphs greedy strings Statement D Codeforces Round 961 (Div. 2) {1995} PROGRAMMING 2250.0 Video Tutorial
3963 Expected Power bitmasks brute force dp math number theory probabilities Statement E Codeforces Round 976 (Div. 2) and Divide By Zero 9.0 {2020} PROGRAMMING 2000.0 Tutorial for Codeforces Round 976 (Div. 2) and Divide By Zero 9.0
25821 Find Minimum Operations bitmasks greedy math Statement A Codeforces Round 976 (Div. 2) and Divide By Zero 9.0 {2020} PROGRAMMING 500.0 Tutorial for Codeforces Round 976 (Div. 2) and Divide By Zero 9.0
18233 Bitwise Balancing bitmasks implementation math Statement C Codeforces Round 976 (Div. 2) and Divide By Zero 9.0 {2020} PROGRAMMING 1250.0 Tutorial for Codeforces Round 976 (Div. 2) and Divide By Zero 9.0
2005 Best Subsequence bitmasks dfs and similar flows graph matchings graphs Statement E Educational Codeforces Round 171 (Rated for Div. 2) {2026} PROGRAMMING Educational Codeforces Round 171 Editorial
247 Bit Game (Easy Version) bitmasks brute force games math Statement E1 Codeforces Round 982 (Div. 2) {2027} PROGRAMMING 2000.0 Codeforces Round #982 (Div. 2) Editorial
109 Bit Game (Hard Version) bitmasks dp math Statement E2 Codeforces Round 982 (Div. 2) {2027} PROGRAMMING 1000.0 Codeforces Round #982 (Div. 2) Editorial
533 Alice's Adventures in Addition bitmasks dp implementation Statement F Codeforces Round 986 (Div. 2) {2028} PROGRAMMING 2500.0 Codeforces Round 986 (Div. 2) Editorial
110 Message Spread bitmasks combinatorics dp Statement H Refact.ai Match 1 (Codeforces Round 985) {2029} PROGRAMMING 5000.0 Refact.ai Match 1 (Codeforces Round 985) Editorial
8574 QED's Favorite Permutation bitmasks data structures implementation sortings Statement D Codeforces Round 979 (Div. 2) {2030} PROGRAMMING 1500.0 Codeforces Round 979 Editorial
11480 Alya and Permutation bitmasks constructive algorithms data structures Statement C Codeforces Global Round 27 {2035} PROGRAMMING 1000.0 Codeforces Global Round 27 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
5236 XORificator 3000 bitmasks dp number theory Statement F Codeforces Round 984 (Div. 3) {2036} PROGRAMMING Codeforces Round 984 (Div. 3) Editorial
854 Divide OR Conquer bitmasks data structures dp implementation Statement D 2024-2025 ICPC, NERC, Southern and Volga Russian Regional Contest (Unrated, Online Mirror, ICPC Rules, Preferably Teams) {2038} PROGRAMMING 2400
13464 Shohag Loves XOR (Easy Version) bitmasks brute force math number theory Statement C1 CodeTON Round 9 (Div. 1 + Div. 2, Rated, Prizes!) {2039} PROGRAMMING 1000.0 Editorial of CodeTON Round 9 (Div. 1 + Div. 2)
4955 Shohag Loves XOR (Hard Version) bitmasks brute force math number theory Statement C2 CodeTON Round 9 (Div. 1 + Div. 2, Rated, Prizes!) {2039} PROGRAMMING 1500.0 Editorial of CodeTON Round 9 (Div. 1 + Div. 2)
1996 Cube bitmasks dp Statement C 2024 ICPC Asia Taichung Regional Contest (Unrated, Online Mirror, ICPC Rules, Preferably Teams) {2041} PROGRAMMING Problem Analysis and Hints (PDF)
1816 Matrix Transformation bitmasks brute force dfs and similar graphs implementation Statement E Educational Codeforces Round 173 (Rated for Div. 2) {2043} PROGRAMMING Educational Codeforces Round 173 Editorial
900 Nim bitmasks dp games Statement F Educational Codeforces Round 173 (Rated for Div. 2) {2043} PROGRAMMING Educational Codeforces Round 173 Editorial
336 Xorderable Array bitmasks data structures Statement J 2024-2025 ICPC Asia Jakarta Regional Contest (Unrated, Online Mirror, ICPC Rules, Teams Preferred) {2045} PROGRAMMING raRzKDJLPHcUnqTcwvGznwEdKiDWjEkd.pdf 2600
15081 Kevin and Binary Strings bitmasks brute force greedy strings Statement C Codeforces Global Round 28 {2048} PROGRAMMING 1000.0 Tutorial
57 Kevin and Puzzle (Hard Version) bitmasks fft math Statement I2 Codeforces Global Round 28 {2048} PROGRAMMING 3000.0 Tutorial
1582 Broken Queries binary search bitmasks interactive Statement E Codeforces Round 994 (Div. 2) {2049} PROGRAMMING 2250.0 Codeforces Round #994 (Div. 2) Editorial
577 MEX OR Mania bitmasks data structures implementation Statement F Codeforces Round 994 (Div. 2) {2049} PROGRAMMING 2750.0 Codeforces Round #994 (Div. 2) Editorial
2419 Snakes bitmasks dp graphs Statement G Codeforces Round 995 (Div. 3) {2051} PROGRAMMING 137623
12294 Bewitching Stargazer bitmasks divide and conquer dp math Statement C Good Bye 2024: 2025 is NEAR {2053} PROGRAMMING 1250.0 Good Bye 2024: 2025 is NEAR Editorial
344 Xor of Median (Hard Version) bitmasks combinatorics Statement F2 Codeforces Round 997 (Div. 2) {2056} PROGRAMMING 1250.0 Codeforces Round #997 (Div. 2) Editorial
435 Xor of Median (Easy Version) bitmasks combinatorics dp math Statement F1 Codeforces Round 997 (Div. 2) {2056} PROGRAMMING 2750.0 Codeforces Round #997 (Div. 2) Editorial
13696 Trip to the Olympiad bitmasks constructive algorithms greedy math Statement C Hello 2025 {2057} PROGRAMMING 1500.0
3938 Kevin and And bitmasks brute force dp greedy Statement E IAEPC Preliminary Contest (Codeforces Round 999, Div. 1 + Div. 2) {2061} PROGRAMMING 2000.0 IAEPC Preliminary Contest (Codeforces Round 999, Div. 1 + Div. 2) Editorial
174 Galaxy Generator bitmasks combinatorics dp Statement H Ethflow Round 1 (Codeforces Round 1001, Div. 1 + Div. 2) {2062} PROGRAMMING 4500.0 Ethflow Round 1 (Codeforces Round 1001, Div. 1 + Div. 2) Editorial
5819 Eating binary search bitmasks data structures greedy two pointers Statement D Codeforces Round 1005 (Div. 2) {2064} PROGRAMMING 1750.0 Codeforces Round 1005 (Div. 2) Editorial
2444 Bitwise Slides bitmasks combinatorics dp math Statement C Codeforces Round 1004 (Div. 1) {2066} PROGRAMMING 1250.0 139415
1073 Infinite Sequence (Hard Version) bitmasks constructive algorithms data structures dp implementation math Statement D2 Codeforces Round 1007 (Div. 2) {2071} PROGRAMMING 1250.0 Codeforces Round 1007 (Div. 2) Editorial
6636 Infinite Sequence (Easy Version) bitmasks dp math Statement D1 Codeforces Round 1007 (Div. 2) {2071} PROGRAMMING 1750.0 Codeforces Round 1007 (Div. 2) Editorial
8401 Goodbye, Banker Life bitmasks combinatorics constructive algorithms math number theory Statement F Codeforces Round 1006 (Div. 3) {2072} PROGRAMMING Codeforces Round 1006 (Div. 3) Editorial
19460 Creating Keys for StORages Has Become My Main Skill bitmasks constructive algorithms greedy Statement C Codeforces Round 1006 (Div. 3) {2072} PROGRAMMING Codeforces Round 1006 (Div. 3) Editorial
21908 XOR and Triangle binary search bitmasks brute force greedy Statement C Codeforces Round 1009 (Div. 3) {2074} PROGRAMMING Codeforces Round 1009 (Div. 3) — Editorial
2462 Counting Necessary Nodes bitmasks divide and conquer implementation math Statement F Codeforces Round 1009 (Div. 3) {2074} PROGRAMMING Codeforces Round 1009 (Div. 3) — Editorial
5758 Equalization bitmasks brute force dp greedy math Statement D Educational Codeforces Round 176 (Rated for Div. 2) {2075} PROGRAMMING Educational Codeforces Round 176 Editorial
1147 XOR Matrix bitmasks dp Statement E Educational Codeforces Round 176 (Rated for Div. 2) {2075} PROGRAMMING Educational Codeforces Round 176 Editorial
133 RGB Walking bitmasks chinese remainder theorem dfs and similar graphs number theory Statement G Codeforces Round 1008 (Div. 1) {2077} PROGRAMMING 3000.0 Codeforces Round 1008 (Div. 1, Div. 2) Editorial
258 AND x OR bitmasks constructive algorithms dp Statement F Codeforces Round 1008 (Div. 1) {2077} PROGRAMMING 2500.0 Codeforces Round 1008 (Div. 1, Div. 2) 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
4053 Math Division bitmasks dp math probabilities Statement A Codeforces Round 1010 (Div. 1, Unrated) {2081} PROGRAMMING 500.0 Codeforces Round 1010 (Div. 1, Div. 2, based on Zhili Cup 2025) Editorial
353 Quaternary Matrix bitmasks greedy Statement C Codeforces Round 1010 (Div. 1, Unrated) {2081} PROGRAMMING 1750.0 Codeforces Round 1010 (Div. 1, Div. 2, based on Zhili Cup 2025) Editorial
13466 Serval and The Formula bitmasks constructive algorithms greedy Statement C Codeforces Round 1011 (Div. 2) {2085} PROGRAMMING 1250.0 Codeforces Round #1011 (Div. 2) Editorial
1656 Zebra-like Numbers bitmasks brute force dfs and similar dp math Statement E Educational Codeforces Round 177 (Rated for Div. 2) {2086} PROGRAMMING Educational Codeforces Round 177 Editorial
5856 Hackers and Neural Networks bitmasks brute force greedy Statement F Codeforces Round 1016 (Div. 3) {2093} PROGRAMMING Codeforces Round 1016 (Div. 3) Editorial
12229 Skibidi Table bitmasks implementation Statement D Codeforces Round 1016 (Div. 3) {2093} PROGRAMMING Codeforces Round 1016 (Div. 3) Editorial
18479 Boneca Ambalabu bitmasks Statement E Codeforces Round 1017 (Div. 4) {2094} PROGRAMMING Codeforces Round 1017 (Div. 4) Editorial
222 Wonderful XOR Problem bitmasks combinatorics dp fft math Statement H Neowise Labs Contest 1 (Codeforces Round 1018, Div. 1 + Div. 2) {2096} PROGRAMMING 3500.0 Neowise Labs Contest 1 (Codeforces Round 1018, Div. 1 + Div. 2) Editorial
5573 Wonderful Lightbulbs bitmasks math Statement D Neowise Labs Contest 1 (Codeforces Round 1018, Div. 1 + Div. 2) {2096} PROGRAMMING 1750.0 Neowise Labs Contest 1 (Codeforces Round 1018, Div. 1 + Div. 2) Editorial
529 Homework bitmasks math matrices Statement D Codeforces Round 1021 (Div. 1) {2097} PROGRAMMING 2000.0 142316
609 Maximize Nor bitmasks data structures implementation Statement F Codeforces Round 1019 (Div. 2) {2103} PROGRAMMING 3000.0 142149
14479 SUMdamental Decomposition bitmasks constructive algorithms greedy implementation math Statement B Codeforces Round 1022 (Div. 2) {2108} PROGRAMMING 1250.0 Codeforces Round 1022 Editorial
11324 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
17232 Slice to Survive bitmasks greedy Statement B Codeforces Round 1025 (Div. 2) {2109} PROGRAMMING 1000.0 Codeforces Round 1025 (Div. 2) Editorial
5476 Small Operations binary search bitmasks brute force dfs and similar dp math number theory sortings Statement F Codeforces Round 1027 (Div. 3) {2114} PROGRAMMING 143268
2026 Build an Array bitmasks dp math number theory Statement G Codeforces Round 1027 (Div. 3) {2114} PROGRAMMING 143268
1050 Gellyfish and Forget-Me-Not bitmasks games math Statement D Codeforces Round 1028 (Div. 1) {2115} PROGRAMMING 2250.0 Codeforces Round 1028 (Div.1, Div.2) Editorial
18346 Make It Beautiful bitmasks greedy math Statement C Codeforces Round 1030 (Div. 2) {2118} PROGRAMMING 1000.0 Codeforces Round 1030 (Div. 2) Editorial
16154 A Good Problem bitmasks constructive algorithms math Statement C Codeforces Round 1035 (Div. 2) {2119} PROGRAMMING 1500.0 Codeforces Round 1035 (Div. 2) Editorial
698 And Constraint bitmasks dp greedy implementation Statement E Codeforces Round 1035 (Div. 2) {2119} PROGRAMMING 2500.0 Codeforces Round 1035 (Div. 2) Editorial
104 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
1655 Interactive RBS (Hard Version) binary search bitmasks constructive algorithms dp interactive Statement C3 Codeforces Round 1040 (Div. 1) {2129} PROGRAMMING 750.0 Codeforces Round 1040 (Div. 1, Div. 2) Editorial
3835 Interactive RBS (Easy Version) binary search bitmasks constructive algorithms interactive Statement C1 Codeforces Round 1040 (Div. 1) {2129} PROGRAMMING 750.0 Codeforces Round 1040 (Div. 1, Div. 2) Editorial
2485 Interactive RBS (Medium Version) binary search bitmasks constructive algorithms interactive Statement C2 Codeforces Round 1040 (Div. 1) {2129} PROGRAMMING 750.0 Codeforces Round 1040 (Div. 1, Div. 2) Editorial
3735 Wafu! bitmasks brute force dp math Statement G Codeforces Round 1042 (Div. 3) {2131} PROGRAMMING Codeforces Round 1042 (Div. 3) Editorial
3853 By the Assignment bitmasks dfs and similar dsu graphs Statement C Codeforces Round 1046 (Div. 1) {2135} PROGRAMMING 1750.0 Codeforces Round 1046 (Div. 1, Div. 2) Editorial
3340 Maple and Tree Beauty (Hard Version) bitmasks brute force dfs and similar divide and conquer dp fft trees Statement C2 Codeforces Round 1048 (Div. 1) {2138} PROGRAMMING 750.0 Codeforces Round 1048 (Div. 1, Div. 2) Editorial
16914 Cake Assignment bitmasks constructive algorithms Statement A Codeforces Round 1048 (Div. 1) {2138} PROGRAMMING 500.0 Codeforces Round 1048 (Div. 1, Div. 2) Editorial
2085 Prime Gaming (Easy Version) bitmasks combinatorics dp Statement E1 Codeforces Round 1049 (Div. 2) {2140} PROGRAMMING 1750.0 Codeforces Round 1049 (Div. 2) Editorial
1225 Prime Gaming (Hard Version) bitmasks combinatorics dp probabilities Statement E2 Codeforces Round 1049 (Div. 2) {2140} PROGRAMMING 1000.0 Codeforces Round 1049 (Div. 2) Editorial
4004 Max Sum OR (Hard Version) bitmasks constructive algorithms divide and conquer greedy Statement D2 Codeforces Round 1052 (Div. 2) {2146} PROGRAMMING 1000.0 Codeforces Round 1052 (Div. 2) Editorial
10346 Max Sum OR (Easy Version) bitmasks constructive algorithms divide and conquer greedy trees Statement D1 Codeforces Round 1052 (Div. 2) {2146} PROGRAMMING 1500.0 Codeforces Round 1052 (Div. 2) Editorial
2106 Maximum OR Popcount binary search bitmasks brute force data structures greedy Statement E Codeforces Global Round 29 (Div. 1 + Div. 2) {2147} PROGRAMMING 2500.0
6703 Division Versus Addition bitmasks data structures games Statement D Squarepoint Challenge (Codeforces Round 1055, Div. 1 + Div. 2) {2152} PROGRAMMING 2500.0 Squarepoint Challenge (Codeforces Round 1055, Div. 1 + Div. 2) Editorial
22499 Bitwise Reversion bitmasks Statement B Codeforces Round 1057 (Div. 2) {2153} PROGRAMMING 750.0 Codeforces Round 1057 (Div. 2) Editorial
5337 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
15014 Reverse XOR bitmasks Statement C Codeforces Round 1058 (Div. 2) {2160} PROGRAMMING 1250.0 Codeforces Round 1058 Editorial
89 Bitwise And Equals bitmasks Statement G Pinely Round 5 (Div. 1 + Div. 2) {2161} PROGRAMMING 3750.0
21138 Beautiful XOR bitmasks constructive algorithms Statement C Codeforces Round 1059 (Div. 3) {2162} PROGRAMMING Codeforces Round 1059 (Div. 3) Editorial
3470 Binary Wine bitmasks greedy Statement C Codeforces Round 1064 (Div. 1) {2165} PROGRAMMING 1500.0 148452
867 Intercepting Butterflies bitmasks constructive algorithms graphs interactive Statement C Testing Round 20 (Unrated, Communication Problems) {2168} PROGRAMMING Testing Round 20 Editorial (officially unofficial)
3289 Encode and Decode (Hard Version) bitmasks interactive math Statement A2 Testing Round 20 (Unrated, Communication Problems) {2168} PROGRAMMING Testing Round 20 Editorial (officially unofficial)
8453 Removal of a Sequence (Easy Version) binary search bitmasks geometry implementation math number theory Statement D1 Educational Codeforces Round 184 (Rated for Div. 2) {2169} PROGRAMMING Educational Codeforces Round 184 Editorial
768 Build XOR on a Segment bitmasks dp Statement F Educational Codeforces Round 185 (Rated for Div. 2) {2170} PROGRAMMING Educational Codeforces Round 185 Editorial
2292 Sakura Adachi and Optimal Sequences bitmasks combinatorics greedy math Statement G Codeforces Round 1065 (Div. 3) {2171} PROGRAMMING Codeforces Round 1065 (Div. 3) Editorial
11720 Renako Amaori and XOR Game (hard version) bitmasks games greedy Statement C2 Codeforces Round 1065 (Div. 3) {2171} PROGRAMMING Codeforces Round 1065 (Div. 3) Editorial
3588 Taiga's Carry Chains bitmasks brute force dp greedy Statement D Codeforces Round 1068 (Div. 2) {2173} PROGRAMMING 1750.0
1463 Omega Numbers bitmasks dp math number theory Statement F Codeforces Round 1070 (Div. 2) {2176} PROGRAMMING 2750.0 Codeforces Round 1070 (Div.2) Editorial
22733 Optimal Shifts bitmasks greedy strings Statement B Codeforces Round 1070 (Div. 2) {2176} PROGRAMMING 1000.0 Codeforces Round 1070 (Div.2) Editorial
13361 Blackslex and Penguin Civilization bitmasks constructive algorithms greedy math Statement D Codeforces Round 1071 (Div. 3) {2179} PROGRAMMING Codeforces Round 1071 (Div. 3) Editorial
1291 Blackslex and Plants bitmasks data structures dp math Statement H Codeforces Round 1071 (Div. 3) {2179} PROGRAMMING Codeforces Round 1071 (Div. 3) Editorial
6386 XOR-factorization bitmasks constructive algorithms dp greedy number theory Statement C Codeforces Global Round 31 (Div. 1 + Div. 2) {2180} PROGRAMMING 1500.0 Codeforces Global Round 31
1725 No Effect XOR bitmasks math Statement E Codeforces Global Round 31 (Div. 1 + Div. 2) {2180} PROGRAMMING 2000.0 Codeforces Global Round 31
1258 Christmas Reindeer (easy version) bitmasks combinatorics dp Statement F1 Educational Codeforces Round 186 (Rated for Div. 2) {2182} PROGRAMMING Educational Codeforces Round 186 Editorial
1081 Christmas Reindeer (hard version) bitmasks combinatorics dp Statement F2 Educational Codeforces Round 186 (Rated for Div. 2) {2182} PROGRAMMING Educational Codeforces Round 186 Editorial
609 Cool Problem bitmasks brute force divide and conquer dp math Statement D Codeforces Round 1077 (Div. 1) {2187} PROGRAMMING 2000.0 Codeforces Round 1077 (Div. 1, Div. 2) Editorial
5179 Shortest Statement Ever bitmasks constructive algorithms dp greedy Statement B Codeforces Round 1077 (Div. 1) {2187} PROGRAMMING 1250.0 Codeforces Round 1077 (Div. 1, Div. 2) Editorial
13730 XOR Convenience (Easy Version) bitmasks brute force constructive algorithms math Statement C1 Codeforces Round 1075 (Div. 2) {2189} PROGRAMMING 1250.0 Codeforces Round 1075 (Div. 2) Editorial
6133 XOR-convenience (Hard Version) bitmasks brute force constructive algorithms math Statement C2 Codeforces Round 1075 (Div. 2) {2189} PROGRAMMING 750.0 Codeforces Round 1075 (Div. 2) Editorial
91 Xor Product bitmasks dp Statement F Codeforces Round 1073 (Div. 1) {2190} PROGRAMMING 3500.0 Codeforces Round 1073 (Div. 1, Div. 2) Editorial
166 Again Trees... (hard version) bitmasks data structures dfs and similar dp fft trees Statement F2 Codeforces Round 1078 (Div. 2) {2194} PROGRAMMING 1750.0 Codeforces Round #1078 Editorial
871 Again Trees... (Easy Version) bitmasks dfs and similar dp fft trees Statement F1 Codeforces Round 1078 (Div. 2) {2194} PROGRAMMING 1750.0 Codeforces Round #1078 Editorial
10708 Secret message bitmasks math Statement C Codeforces Round 1078 (Div. 2) {2194} PROGRAMMING 1750.0 Codeforces Round #1078 Editorial
274 Fuzzy Concatenation (Easy Version) binary search bitmasks brute force data structures greedy string suffix structures Statement E1 Codeforces Round 1079 (Div. 1) {2196} PROGRAMMING 2000.0 Tutorial
6736 Test Generator binary search bitmasks greedy math Statement C Educational Codeforces Round 187 (Rated for Div. 2) {2203} PROGRAMMING Educational Codeforces Round 187 Editorial
195 Simons and Diophantus Equation bitmasks brute force data structures number theory Statement G Codeforces Round 1083 (Div. 2) {2205} PROGRAMMING 3250.0 Tutorial
2734 AND-array bitmasks combinatorics math Statement D Nebius Round 2 (Codeforces Round 1088, Div. 1 + Div. 2) {2211} PROGRAMMING 2000.0 Nebius Round 2 and Codeforces Round 1088 Editorial
78 EXPloration, EXPloitation, and Gain Some EXPerience! bitmasks brute force dp greedy implementation Statement D Codeforces Round 1092 (Unrated, Div. 1, Based on THUPC 2026 — Finals) {2215} PROGRAMMING 2750.0
477 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
589 Interval Game bitmasks combinatorics dp games greedy math probabilities Statement F Codeforces Round 1091 (Div. 2) and CodeCraft 26 {2217} PROGRAMMING 2750.0
12604 The 67th XOR Problem binary search bitmasks brute force trees Statement E Codeforces Round 1090 (Div. 4) {2218} PROGRAMMING