Index Problem Difficulty Solved 1 Squares and not squares 1600 2 Comments 1700 3 Numbers Exchange 1800 4 Tree Reconstruction 1900 5 Mahmoud and Ehab and the xor-MST 1900 6 Maximize! 1900 7 Game of Stones 2000 8 The LCMs Must be Large 2000 9 Minimizing Difference 2000 10 Cashback 2000 11 Petya and Construction Set 2000 12 Danil and a Part-time Job 2000 13 Editor 2000 14 Polycarp and Snakes 2000 15 Hanoi Factory 2000 16 Dasha and Puzzle 2000 17 Sergey and Subway 2000 18 Compress Words 2000 19 Fire 2000 20 Trips 2100 21 Beautiful Mirrors 2100 22 Arithmetic Progression 2100 23 OpenStreetMap 2100 24 Number of Components 2100 25 Serval and Snake 2100 26 Segments Removal 2100 27 Coprocessor 2100 28 Lunar New Year and Red Envelopes 2100 29 Down or Right 2100 30 The Holmes Children 2100 31 Congruence Equation 2100 32 Common Number 2100 33 Product Oriented Recurrence 2200 34 Okabe and El Psy Kongroo 2200 35 Helping Hiasat 2200 36 Tourism 2200 37 Antenna Coverage 2200 38 Tree Folding 2200 39 Let Them Slide 2200 40 Alternating Tree 2200 41 Mahmoud and a xor trip 2200 42 Sagheer and Apple Tree 2200 43 Marbles 2200 44 Hyakugoku and Ladders 2300 45 Maximum Questions 2300 46 Birds 2300 47 Anton and Permutation 2300 48 The Number Games 2300 49 Vladik and cards 2300 50 Company 2300 51 Another Filling the Grid 2300 52 Vasya and Magic Matrix 2300 53 The Untended Antiquity 2300 54 The penguin's game 2400 55 The Cake Is a Lie 2400 56 Split the Tree 2400 57 Ehab and a component choosing problem 2400 58 Restore Array 2400 59 Bash Plays with Functions 2400 60 Sonya and Matrix Beauty 2400 61 Natasha, Sasha and the Prefix Sums 2400 62 Team Work 2400 63 Maximum Matching 2400 64 Ralph and Mushrooms 2400 65 Sonya and Ice Cream 2400 66 The Supersonic Rocket 2400 67 Palindromes in a Tree 2400 68 Eyes Closed 2500 69 Billiard 2500 70 Aquarium decoration 2500 71 Ehab and the Expected GCD Problem 2500 72 Neko and Flashback 2500 73 Vus the Cossack and a Field 2500 74 Nastya Hasn't Written a Legend 2500 75 Fafa and Ancient Mathematics 2500 76 Short Code 2500 77 Liar 2500 78 Policeman and a Tree 2600 79 Alice and the Unfair Game 2600 80 Colored Cubes 2600 81 Vladik and Entertaining Flags 2600 82 Inversions After Shuffle 2600 83 Jamie and Tree 2600 84 Mother of Dragons 2600 85 Nastya and King-Shamans 2600 86 Prime Gift 2600 87 Choosing Carrot 2700 88 An unavoidable detour for home 2700 89 Change-free 2700 90 Vasya and Shifts 2700 91 Little Brother 2700 92 Mike and code of a permutation 2700 93 Kuro and Topological Parity 2800 94 Dasha and cyclic table 2800 95 Magical Permutation 2800 96 Tree 2800 97 A Trance of Nightfall 2900 98 Broken Tree 2900 99 Icicles 2900 100 Hag's Khashba 3000