Sorted by frequency
| 42 | Trapping Rain Water | 45.7% | Hard | |
| 4 | Median of Two Sorted Arrays | 27.8% | Hard | |
| 23 | Merge k Sorted Lists | 37.0% | Hard | |
| 76 | Minimum Window Substring | 32.5% | Hard | |
| 273 | Integer to English Words | 25.3% | Hard | |
| 301 | Remove Invalid Parentheses | 41.0% | Hard | |
| 1192 | Critical Connections in a Network | 48.5% | Hard | |
| 297 | Serialize and Deserialize Binary Tree | 43.7% | Hard | |
| 68 | Text Justification | 24.9% | Hard | |
| 336 | Palindrome Pairs | 32.2% | Hard | |
| 269 | Alien Dictionary | 33.2% | Hard | |
| 41 | First Missing Positive | 30.2% | Hard | |
| 10 | Regular Expression Matching | 25.9% | Hard | |
| 85 | Maximal Rectangle | 35.1% | Hard | |
| 741 | Cherry Pickup | 32.2% | Hard | |
| 218 | The Skyline Problem | 32.8% | Hard | |
| 312 | Burst Balloons | 49.1% | Hard | |
| 642 | Design Search Autocomplete System | 41.1% | Hard | |
| 124 | Binary Tree Maximum Path Sum | 31.6% | Hard | |
| 32 | Longest Valid Parentheses | 26.7% | Hard | |
| 45 | Jump Game II | 29.2% | Hard | |
| 72 | Edit Distance | 40.2% | Hard | |
| 759 | Employee Free Time | 63.3% | Hard | |
| 410 | Split Array Largest Sum | 43.3% | Hard | |
| 295 | Find Median from Data Stream | 39.7% | Hard | |
| 212 | Word Search II | 30.9% | Hard | |
| 460 | LFU Cache | 31.2% | Hard | |
| 51 | N-Queens | 42.4% | Hard | |
| 97 | Interleaving String | 29.4% | Hard | |
| 315 | Count of Smaller Numbers After Self | 40.0% | Hard | |
| 44 | Wildcard Matching | 23.7% | Hard | |
| 158 | Read N Characters Given Read4 II - Call multiple times | 29.3% | Hard | |
| 25 | Reverse Nodes in k-Group | 38.6% | Hard | |
| 780 | Reaching Points | 28.4% | Hard | |
| 57 | Insert Interval | 32.1% | Hard | |
| 65 | Valid Number | 14.5% | Hard | |
| 37 | Sudoku Solver | 39.6% | Hard | |
| 224 | Basic Calculator | 34.7% | Hard | |
| 140 | Word Break II | 28.8% | Hard | |
| 149 | Max Points on a Line | 16.3% | Hard | |
| 126 | Word Ladder II | 19.6% | Hard | |
| 128 | Longest Consecutive Sequence | 43.2% | Hard | |
| 317 | Shortest Distance from All Buildings | 39.5% | Hard | |
| 123 | Best Time to Buy and Sell Stock III | 35.4% | Hard | |
| 239 | Sliding Window Maximum | 40.0% | Hard | |
| 403 | Frog Jump | 37.5% | Hard | |
| 843 | Guess the Word | 45.2% | Hard | |
| 340 | Longest Substring with At Most K Distinct Characters | 41.7% | Hard | |
| 736 | Parse Lisp Expression | 45.6% | Hard | |
| 428 | Serialize and Deserialize N-ary Tree | 56.3% | Hard | |
| 772 | Basic Calculator III | 41.2% | Hard | |
| 214 | Shortest Palindrome | 28.4% | Hard | |
| 829 | Consecutive Numbers Sum | 35.4% | Hard | |
| 964 | Least Operators to Express Number | 41.7% | Hard | |
| 472 | Concatenated Words | 38.4% | Hard | |
| 887 | Super Egg Drop | 25.8% | Hard | |
| 679 | 24 Game | 44.3% | Hard | |
| 30 | Substring with Concatenation of All Words | 24.4% | Hard | |
| 1163 | Last Substring in Lexicographical Order | 31.1% | Hard | |
| 432 | All O`one Data Structure | 30.9% | Hard | |
| 591 | Tag Validator | 33.4% | Hard | |
| 84 | Largest Rectangle in Histogram | 32.7% | Hard | |
| 329 | Longest Increasing Path in a Matrix | 41.5% | Hard | |
| 316 | Remove Duplicate Letters | 33.8% | Hard | |
| 588 | Design In-Memory File System | 42.3% | Hard | |
| 188 | Best Time to Buy and Sell Stock IV | 27.1% | Hard | |
| 773 | Sliding Puzzle | 55.4% | Hard | |
| 420 | Strong Password Checker | 16.4% | Hard | |
| 99 | Recover Binary Search Tree | 36.3% | Hard | |
| 564 | Find the Closest Palindrome | 19.2% | Hard | |
| 465 | Optimal Account Balancing | 44.9% | Hard | |
| 1096 | Brace Expansion II | 60.6% | Hard | |
| 440 | K-th Smallest in Lexicographical Order | 27.6% | Hard | |
| 480 | Sliding Window Median | 34.5% | Hard | |
| 282 | Expression Add Operators | 34.1% | Hard | |
| 730 | Count Different Palindromic Subsequences | 40.4% | Hard | |
| 753 | Cracking the Safe | 48.8% | Hard | |
| 862 | Shortest Subarray with Sum at Least K | 22.9% | Hard | |
| 233 | Number of Digit One | 30.8% | Hard | |
| 363 | Max Sum of Rectangle No Larger Than K | 35.8% | Hard | |
| 1032 | Stream of Characters | 45.7% | Hard | |
| 321 | Create Maximum Number | 26.0% | Hard | |
| 381 | Insert Delete GetRandom O(1) - Duplicates allowed | 33.0% | Hard | |
| 980 | Unique Paths III | 71.6% | Hard | |
| 296 | Best Meeting Point | 56.3% | Hard | |
| 489 | Robot Room Cleaner | 67.1% | Hard | |
| 407 | Trapping Rain Water II | 40.2% | Hard | |
| 1036 | Escape a Large Maze | 35.0% | Hard | |
| 834 | Sum of Distances in Tree | 41.6% | Hard | |
| 354 | Russian Doll Envelopes | 34.6% | Hard | |
| 943 | Find the Shortest Superstring | 40.7% | Hard | |
| 828 | Unique Letter String | 42.1% | Hard | |
| 995 | Minimum Number of K Consecutive Bit Flips | 46.3% | Hard | |
| 631 | Design Excel Sum Formula | 30.3% | Hard | |
| 135 | Candy | 29.7% | Hard | |
| 291 | Word Pattern II | 42.3% | Hard | |
| 727 | Minimum Window Subsequence | 39.4% | Hard | |
| 805 | Split Array With Same Average | 25.4% | Hard | |
| 272 | Closest Binary Search Tree Value II | 47.6% | Hard | |
| 761 | Special Binary String | 53.5% | Hard | |
| 1000 | Minimum Cost to Merge Stones | 36.8% | Hard | |
| 895 | Maximum Frequency Stack | 58.6% | Hard | |
| 992 | Subarrays with K Different Integers | 46.0% | Hard | |
| 1240 | Tiling a Rectangle with the Fewest Squares | 48.7% | Hard | |
| 815 | Bus Routes | 41.3% | Hard | |
| 913 | Cat and Mouse | 29.9% | Hard | |
| 164 | Maximum Gap | 33.7% | Hard | |
| 132 | Palindrome Partitioning II | 28.7% | Hard | |
| 975 | Odd Even Jump | 44.7% | Hard | |
| 726 | Number of Atoms | 46.3% | Hard | |
| 185 | Department Top Three Salaries | 29.5% | Hard | |
| 1206 | Design Skiplist | 60.0% | Hard | |
| 691 | Stickers to Spell Word | 40.4% | Hard | |
| 632 | Smallest Range Covering Elements from K Lists | 49.8% | Hard | |
| 493 | Reverse Pairs | 24.0% | Hard | |
| 765 | Couples Holding Hands | 52.9% | Hard | |
| 488 | Zuma Game | 40.2% | Hard | |
| 770 | Basic Calculator IV | 46.0% | Hard | |
| 527 | Word Abbreviation | 52.1% | Hard | |
| 115 | Distinct Subsequences | 36.1% | Hard | |
| 675 | Cut Off Trees for Golf Event | 32.9% | Hard | |
| 920 | Number of Music Playlists | 44.8% | Hard | |
| 335 | Self Crossing | 27.3% | Hard | |
| 982 | Triples with Bitwise AND Equal To Zero | 54.9% | Hard | |
| 358 | Rearrange String k Distance Apart | 33.9% | Hard | |
| 552 | Student Attendance Record II | 34.7% | Hard | |
| 839 | Similar String Groups | 36.3% | Hard | |
| 262 | Trips and Users | 27.7% | Hard | |
| 854 | K-Similar Strings | 36.2% | Hard | |
| 87 | Scramble String | 32.5% | Hard | |
| 1074 | Number of Submatrices That Sum to Target | 59.4% | Hard | |
| 1153 | String Transforms Into Another String | 33.6% | Hard | |
| 601 | Human Traffic of Stadium | 38.6% | Hard | |
| 956 | Tallest Billboard | 38.8% | Hard | |
| 1220 | Count Vowels Permutation | 51.4% | Hard | |
| 1168 | Optimize Water Distribution in a Village | 57.2% | Hard | |
| 391 | Perfect Rectangle | 29.1% | Hard | |
| 330 | Patching Array | 33.8% | Hard | |
| 1106 | Parsing A Boolean Expression | 57.5% | Hard | |
| 1044 | Longest Duplicate Substring | 23.7% | Hard | |
| 871 | Minimum Number of Refueling Stops | 30.4% | Hard | |
| 587 | Erect the Fence | 34.7% | Hard | |
| 1028 | Recover a Tree From Preorder Traversal | 69.3% | Hard | |
| 847 | Shortest Path Visiting All Nodes | 49.1% | Hard | |
| 425 | Word Squares | 45.9% | Hard | |
| 145 | Binary Tree Postorder Traversal | 51.1% | Hard | |
| 431 | Encode N-ary Tree to Binary Tree | 67.3% | Hard | |
| 689 | Maximum Sum of 3 Non-Overlapping Subarrays | 44.7% | Hard | |
| 818 | Race Car | 37.2% | Hard | |
| 1178 | Number of Valid Words for Each Puzzle | 36.1% | Hard | |
| 458 | Poor Pigs | 46.5% | Hard | |
| 466 | Count The Repetitions | 27.6% | Hard | |
| 903 | Valid Permutations for DI Sequence | 46.6% | Hard | |
| 745 | Prefix and Suffix Search | 32.2% | Hard | |
| 1088 | Confusing Number II | 38.8% | Hard | |
| 782 | Transform to Chessboard | 40.1% | Hard | |
| 352 | Data Stream as Disjoint Intervals | 44.5% | Hard | |
| 968 | Binary Tree Cameras | 36.4% | Hard | |
| 685 | Redundant Connection II | 31.7% | Hard | |
| 668 | Kth Smallest Number in Multiplication Table | 43.6% | Hard | |
| 768 | Max Chunks To Make Sorted II | 47.1% | Hard | |
| 1092 | Shortest Common Supersequence | 49.7% | Hard | |
| 857 | Minimum Cost to Hire K Workers | 48.7% | Hard | |
| 936 | Stamping The Sequence | 36.0% | Hard | |
| 499 | The Maze III | 39.1% | Hard | |
| 471 | Encode String with Shortest Length | 45.9% | Hard | |
| 568 | Maximum Vacation Days | 38.9% | Hard | |
| 864 | Shortest Path to Get All Keys | 38.8% | Hard | |
| 327 | Count of Range Sum | 34.0% | Hard | |
| 630 | Course Schedule III | 32.7% | Hard | |
| 1001 | Grid Illumination | 34.9% | Hard | |
| 774 | Minimize Max Distance to Gas Station | 44.1% | Hard | |
| 159 | Longest Substring with At Most Two Distinct Characters | 48.2% | Hard | |
| 906 | Super Palindromes | 30.8% | Hard | |
| 1216 | Valid Palindrome III | 42.4% | Hard | |
| 52 | N-Queens II | 54.5% | Hard | |
| 699 | Falling Squares | 40.7% | Hard | |
| 850 | Rectangle Area II | 46.2% | Hard | |
| 154 | Find Minimum in Rotated Sorted Array II | 40.0% | Hard | |
| 719 | Find K-th Smallest Pair Distance | 30.2% | Hard | |
| 996 | Number of Squareful Arrays | 47.4% | Hard | |
| 660 | Remove 9 | 53.0% | Hard | |
| 265 | Paint House II | 43.0% | Hard | |
| 308 | Range Sum Query 2D - Mutable | 33.5% | Hard | |
| 715 | Range Module | 37.0% | Hard | |
| 927 | Three Equal Parts | 31.4% | Hard | |
| 1095 | Find in Mountain Array | 34.7% | Hard | |
| 1187 | Make Array Strictly Increasing | 40.5% | Hard | |
| 1172 | Dinner Plate Stacks | 40.6% | Hard | |
| 786 | K-th Smallest Prime Fraction | 41.4% | Hard | |
| 827 | Making A Large Island | 44.2% | Hard | |
| 174 | Dungeon Game | 28.4% | Hard | |
| 305 | Number of Islands II | 40.8% | Hard | |
| 1231 | Divide Chocolate | 50.2% | Hard | |
| 639 | Decode Ways II | 25.7% | Hard | |
| 710 | Random Pick with Blacklist | 32.4% | Hard | |
| 757 | Set Intersection Size At Least Two | 37.2% | Hard | |
| 882 | Reachable Nodes In Subdivided Graph | 39.2% | Hard | |
| 952 | Largest Component Size by Common Factor | 28.2% | Hard | |
| 1157 | Online Majority Element In Subarray | 33.9% | Hard | |
| 798 | Smallest Rotation with Highest Score | 41.8% | Hard | |
| 732 | My Calendar III | 57.3% | Hard | |
| 878 | Nth Magical Number | 26.9% | Hard | |
| 1203 | Sort Items by Groups Respecting Dependencies | 44.4% | Hard | |
| 891 | Sum of Subsequence Widths | 30.4% | Hard | |
| 924 | Minimize Malware Spread | 41.1% | Hard | |
| 803 | Bricks Falling When Hit | 29.5% | Hard | |
| 446 | Arithmetic Slices II - Subsequence | 31.4% | Hard | |
| 664 | Strange Printer | 38.2% | Hard | |
| 940 | Distinct Subsequences II | 40.8% | Hard | |
| 546 | Remove Boxes | 39.8% | Hard | |
| 248 | Strobogrammatic Number III | 37.9% | Hard | |
| 778 | Swim in Rising Water | 49.8% | Hard | |
| 1235 | Maximum Profit in Job Scheduling | 44.3% | Hard | |
| 1250 | Check If It Is a Good Array | 50.2% | Hard | |
| 656 | Coin Path | 27.7% | Hard | |
| 479 | Largest Palindrome Product | 28.0% | Hard | |
| 902 | Numbers At Most N Given Digit Set | 29.5% | Hard | |
| 644 | Maximum Average Subarray II | 30.1% | Hard | |
| 629 | K Inverse Pairs Array | 30.1% | Hard | |
| 1224 | Maximum Equal Frequency | 31.7% | Hard | |
| 600 | Non-negative Integers without Consecutive Ones | 33.3% | Hard | |
| 1199 | Minimum Time to Build Blocks | 33.4% | Hard | |
| 1263 | Minimum Moves to Move a Box to Their Target Location | 34.4% | Hard | |
| 483 | Smallest Good Base | 34.7% | Hard | |
| 683 | K Empty Slots | 34.9% | Hard | |
| 579 | Find Cumulative Salary of an Employee | 35.1% | Hard | |
| 1012 | Numbers With Repeated Digits | 35.5% | Hard | |
| 411 | Minimum Unique Word Abbreviation | 35.5% | Hard | |
| 517 | Super Washing Machines | 37.4% | Hard | |
| 879 | Profitable Schemes | 37.9% | Hard | |
| 1067 | Digit Count in Range | 38.4% | Hard | |
| 502 | IPO | 38.6% | Hard | |
| 928 | Minimize Malware Spread II | 39.5% | Hard | |
| 793 | Preimage Size of Factorial Zeroes Function | 39.5% | Hard | |
| 972 | Equal Rational Numbers | 40.4% | Hard | |
| 615 | Average Salary: Departments VS Company | 40.8% | Hard | |
| 514 | Freedom Trail | 41.4% | Hard | |
| 749 | Contain Virus | 42.2% | Hard | |
| 1246 | Palindrome Removal | 42.5% | Hard | |
| 1210 | Minimum Moves to Reach Target with Rotations | 43.2% | Hard | |
| 1125 | Smallest Sufficient Team | 44.8% | Hard | |
| 810 | Chalkboard XOR Game | 45.6% | Hard | |
| 571 | Find Median Given Frequency of Numbers | 45.8% | Hard | |
| 618 | Students Report By Geography | 46.3% | Hard | |
| 1127 | User Purchase Platform | 47.4% | Hard | |
| 711 | Number of Distinct Islands II | 47.9% | Hard | |
| 1183 | Maximum Number of Ones | 48.8% | Hard | |
| 899 | Orderly Queue | 49.1% | Hard | |
| 1159 | Market Analysis II | 49.2% | Hard | |
| 302 | Smallest Rectangle Enclosing Black Pixels | 50.3% | Hard | |
| 1259 | Handshakes That Don’t Cross | 51.0% | Hard | |
| 569 | Median Employee Salary | 51.5% | Hard | |
| 1097 | Game Play Analysis V | 51.9% | Hard | |
| 960 | Delete Columns to Make Sorted III | 52.9% | Hard | |
| 1194 | Tournament Winners | 54.8% | Hard | |
| 1121 | Divide Array Into Increasing Sequences | 55.0% | Hard | |
| 1147 | Longest Chunked Palindrome Decomposition | 58.1% | Hard | |
| 1136 | Parallel Courses | 59.3% | Hard | |
| 1225 | Report Contiguous Dates | 62.2% | Hard | |
| 1255 | Maximum Score Words Formed by Letters | 70.8% | Hard | |
| 1063 | Number of Valid Subarrays | 71.6% | Hard |
|---|