Index Problem Difficulty Solved Comments 1 Equality 800 2 Cards 800 3 Love "A" 800 4 New Year and Naming 800 5 Keyboard Layouts 800 6 A Blend of Springtime 900 7 A Serial Killer 900 8 Delete from the Left 900 9 Bark to Unlock 900 10 Comparing Two Long Integers 900 11 Broken Keyboard 1000 12 Reverse a Substring 1000 13 Mike and palindrome 1000 14 Palindromic Twist 1000 15 Diverse Substring 1000 16 Maxim and Biology 1000 17 Code obfuscation 1100 18 Passwords 1100 19 Zuhair and Strings 1100 20 Verse Pattern 1200 21 Login Verification 1200 22 Kuroni and Simple Strings 1200 23 Minimizing the String 1200 24 Letters Cyclic Shift 1200 25 War of the Corporations 1200 26 Bear and Compressing 1300 27 Simple Strings 1300 28 Substring Removal 1300 29 Substring Game in the Lesson 1300 30 Bear and String Distance 1300 31 Mike and strings 1300 32 Subsequence Hate 1400 33 Barnicle 1400 34 String Typing 1400 35 String Modification 1400 36 They Are Everywhere 1500 37 Prefix-Suffix Palindrome (Easy version) 1500 38 Hamming Distance Sum 1500 39 Split a Number 1500 40 Vanya and Label 1500 41 Field of Wonders 1500 42 Hard problem 1600 43 Obtain The String 1600 44 Character Swap (Hard Version) 1600 45 Hidden Word 1600 46 Petya and Exam 1600 47 Shockers 1600 48 Game with String 1600 49 Long Beautiful Integer 1700 50 Prefixes and Suffixes 1700 51 String Game 1700 52 Ayoub's function 1700 53 Palindromic Cut 1800 54 Lexicography 1800 55 Prefix-Suffix Palindrome (Hard version) 1800 56 Reberland Linguistics 1800 57 Make Palindrome 1800 58 Cloud of Hashtags 1800 59 Ugly Pairs 1800 60 Perfect Security 1800 61 Dr. Evil Underscores 1900 62 Subsequences (hard version) 1900 63 Felicity is Coming! 1900 64 Dense Subsequence 1900 65 Spy Syndrome 2 1900 66 Median String 1900 67 New Year and Ancient Prophecy 2000 68 You Are Given a WASD-string... 2100 69 Mysterious Code 2100 70 Messenger 2100 71 Letters Removing 2100 72 String Mark 2100 73 Unstable String Sort 2100 74 Two Bracket Sequences 2200 75 Erase Subsequences 2200 76 Middle-Out 2200 77 Intellectual Inquiry 2200 78 Swapping Characters 2200 79 Huge Strings 2200 80 Fake News (medium) 2200 81 Abbreviation 2200 82 Kaavi and Magic Spell 2200 83 Lock Puzzle 2300 84 Anthem of Berland 2300 85 Bracket Substring 2300 86 kotlinkotlinkotlinkotlin... 2300 87 Morse Code 2400 88 The Supersonic Rocket 2400 89 Refactoring 2400 90 Sonya and Matrix Beauty 2400 91 Reachable Strings 2500 92 Picking Strings 2500 93 Alphabet Permutations 2500 94 Marbles 2500 95 Scissors 2600 96 Two Prefixes 2600 97 Paper task 2600 98 Vasya and Big Integers 2600 99 Awesome Substrings 2600 100 Concatenation with intersection 2700