All companies
Oracle
61 Easy193 Medium59 Hard313 total
| No. | Problem | Difficulty | Frequency |
|---|---|---|---|
| 146 | LRU Cache | Medium | |
| 1 | Two Sum | Easy | |
| 3 | Longest Substring Without Repeating Characters | Medium | |
| 200 | Number of Islands | Medium | |
| 23 | Merge k Sorted Lists | Hard | |
| 49 | Group Anagrams | Medium | |
| 54 | Spiral Matrix | Medium | |
| 56 | Merge Intervals | Medium | |
| 239 | Sliding Window Maximum | Hard | |
| 253 | Meeting Rooms II | Medium | |
| 347 | Top K Frequent Elements | Medium | |
| 20 | Valid Parentheses | Easy | |
| 5 | Longest Palindromic Substring | Medium | |
| 11 | Container With Most Water | Medium | |
| 13 | Roman to Integer | Easy | |
| 15 | 3Sum | Medium | |
| 22 | Generate Parentheses | Medium | |
| 33 | Search in Rotated Sorted Array | Medium | |
| 42 | Trapping Rain Water | Hard | |
| 53 | Maximum Subarray | Medium | |
| 121 | Best Time to Buy and Sell Stock | Easy | |
| 128 | Longest Consecutive Sequence | Medium | |
| 155 | Min Stack | Medium | |
| 199 | Binary Tree Right Side View | Medium | |
| 206 | Reverse Linked List | Easy | |
| 236 | Lowest Common Ancestor of a Binary Tree | Medium | |
| 242 | Valid Anagram | Easy | |
| 394 | Decode String | Medium | |
| 460 | LFU Cache | Hard | |
| 2466 | Count Ways To Build Good Strings | Medium | |
| 2506 | Count Pairs Of Similar Strings | Easy | |
| 2580 | Count Ways to Group Overlapping Ranges | Medium | |
| 2549 | Count Distinct Numbers on Board | Easy | |
| 735 | Asteroid Collision | Medium | |
| 2836 | Maximize Value of Function in a Ball Passing Game | Hard | |
| 994 | Rotting Oranges | Medium | |
| 3012 | Minimize Length of Array Using Operations | Medium | |
| 3015 | Count the Number of Houses at a Certain Distance I | Medium | |
| 3017 | Count the Number of Houses at a Certain Distance II | Hard | |
| 1209 | Remove All Adjacent Duplicates in String II | Medium | |
| 2192 | All Ancestors of a Node in a Directed Acyclic Graph | Medium | |
| 1380 | Lucky Numbers in a Matrix | Easy | |
| 1410 | HTML Entity Parser | Medium | |
| 1611 | Minimum One Bit Operations to Make Integers Zero | Hard | |
| 1797 | Design Authentication Manager | Medium | |
| 1200 | Minimum Absolute Difference | Easy | |
| 3438 | Find Valid Pair of Adjacent Digits in String | Easy | |
| 875 | Koko Eating Bananas | Medium | |
| 4 | Median of Two Sorted Arrays | Hard | |
| 6 | Zigzag Conversion | Medium | |
| 14 | Longest Common Prefix | Easy | |
| 17 | Letter Combinations of a Phone Number | Medium | |
| 34 | Find First and Last Position of Element in Sorted Array | Medium | |
| 41 | First Missing Positive | Hard | |
| 75 | Sort Colors | Medium | |
| 76 | Minimum Window Substring | Hard | |
| 93 | Restore IP Addresses | Medium | |
| 98 | Validate Binary Search Tree | Medium | |
| 103 | Binary Tree Zigzag Level Order Traversal | Medium | |
| 124 | Binary Tree Maximum Path Sum | Hard | |
| 134 | Gas Station | Medium | |
| 138 | Copy List with Random Pointer | Medium | |
| 140 | Word Break II | Hard | |
| 169 | Majority Element | Easy | |
| 207 | Course Schedule | Medium | |
| 210 | Course Schedule II | Medium | |
| 215 | Kth Largest Element in an Array | Medium | |
| 221 | Maximal Square | Medium | |
| 230 | Kth Smallest Element in a BST | Medium | |
| 240 | Search a 2D Matrix II | Medium | |
| 238 | Product of Array Except Self | Medium | |
| 283 | Move Zeroes | Easy | |
| 295 | Find Median from Data Stream | Hard | |
| 300 | Longest Increasing Subsequence | Medium | |
| 322 | Coin Change | Medium | |
| 345 | Reverse Vowels of a String | Easy | |
| 359 | Logger Rate Limiter | Easy | |
| 74 | Search a 2D Matrix | Medium | |
| 380 | Insert Delete GetRandom O(1) | Medium | |
| 443 | String Compression | Medium | |
| 450 | Delete Node in a BST | Medium | |
| 102 | Binary Tree Level Order Traversal | Medium | |
| 525 | Contiguous Array | Medium | |
| 543 | Diameter of Binary Tree | Easy | |
| 588 | Design In-Memory File System | Hard | |
| 621 | Task Scheduler | Medium | |
| 697 | Degree of an Array | Easy | |
| 981 | Time Based Key-Value Store | Medium | |
| 987 | Vertical Order Traversal of a Binary Tree | Hard | |
| 1268 | Search Suggestions System | Medium | |
| 1353 | Maximum Number of Events That Can Be Attended | Medium | |
| 96 | Unique Binary Search Trees | Medium | |
| 2291 | Maximum Profit From Trading Stocks | Medium | |
| 125 | Valid Palindrome | Easy | |
| 71 | Simplify Path | Medium | |
| 647 | Palindromic Substrings | Medium | |
| 51 | N-Queens | Hard | |
| 1669 | Merge In Between Linked Lists | Medium | |
| 208 | Implement Trie (Prefix Tree) | Medium | |
| 755 | Pour Water | Medium | |
| 127 | Word Ladder | Hard | |
| 498 | Diagonal Traverse | Medium | |
| 2954 | Count the Number of Infection Sequences | Hard | |
| 845 | Longest Mountain in Array | Medium | |
| 3799 | Word Squares II | Medium | |
| 2 | Add Two Numbers | Medium | |
| 12 | Integer to Roman | Medium | |
| 21 | Merge Two Sorted Lists | Easy | |
| 26 | Remove Duplicates from Sorted Array | Easy | |
| 40 | Combination Sum II | Medium | |
| 46 | Permutations | Medium | |
| 50 | Pow(x, n) | Medium | |
| 48 | Rotate Image | Medium | |
| 55 | Jump Game | Medium | |
| 61 | Rotate List | Medium | |
| 73 | Set Matrix Zeroes | Medium | |
| 79 | Word Search | Medium | |
| 83 | Remove Duplicates from Sorted List | Easy | |
| 88 | Merge Sorted Array | Easy | |
| 116 | Populating Next Right Pointers in Each Node | Medium | |
| 141 | Linked List Cycle | Easy | |
| 148 | Sort List | Medium | |
| 167 | Two Sum II - Input Array Is Sorted | Medium | |
| 179 | Largest Number | Medium | |
| 205 | Isomorphic Strings | Easy | |
| 209 | Minimum Size Subarray Sum | Medium | |
| 224 | Basic Calculator | Hard | |
| 9 | Palindrome Number | Easy | |
| 234 | Palindrome Linked List | Easy | |
| 237 | Delete Node in a Linked List | Medium | |
| 252 | Meeting Rooms | Easy | |
| 273 | Integer to English Words | Hard | |
| 69 | Sqrt(x) | Easy | |
| 373 | Find K Pairs with Smallest Sums | Medium | |
| 387 | First Unique Character in a String | Easy | |
| 415 | Add Strings | Easy | |
| 463 | Island Perimeter | Easy | |
| 2472 | Maximum Number of Non-overlapping Palindrome Substrings | Hard | |
| 540 | Single Element in a Sorted Array | Medium | |
| 560 | Subarray Sum Equals K | Medium | |
| 2561 | Rearranging Fruits | Hard | |
| 692 | Top K Frequent Words | Medium | |
| 694 | Number of Distinct Islands | Medium | |
| 696 | Count Binary Substrings | Easy | |
| 139 | Word Break | Medium | |
| 739 | Daily Temperatures | Medium | |
| 767 | Reorganize String | Medium | |
| 706 | Design HashMap | Easy | |
| 1010 | Pairs of Songs With Total Durations Divisible by 60 | Medium | |
| 1011 | Capacity To Ship Packages Within D Days | Medium | |
| 1047 | Remove All Adjacent Duplicates In String | Easy | |
| 1235 | Maximum Profit in Job Scheduling | Hard | |
| 378 | Kth Smallest Element in a Sorted Matrix | Medium | |
| 695 | Max Area of Island | Medium | |
| 115 | Distinct Subsequences | Hard | |
| 435 | Non-overlapping Intervals | Medium | |
| 2151 | Maximum Good People Based on Statements | Hard | |
| 912 | Sort an Array | Medium | |
| 114 | Flatten Binary Tree to Linked List | Medium | |
| 217 | Contains Duplicate | Easy | |
| 582 | Kill Process | Medium | |
| 151 | Reverse Words in a String | Medium | |
| 1823 | Find the Winner of the Circular Game | Medium | |
| 1507 | Reformat Date | Easy | |
| 496 | Next Greater Element I | Easy | |
| 198 | House Robber | Medium | |
| 567 | Permutation in String | Medium | |
| 2062 | Count Vowel Substrings of a String | Easy | |
| 153 | Find Minimum in Rotated Sorted Array | Medium | |
| 227 | Basic Calculator II | Medium | |
| 31 | Next Permutation | Medium | |
| 1283 | Find the Smallest Divisor Given a Threshold | Medium | |
| 340 | Longest Substring with At Most K Distinct Characters | Medium | |
| 2303 | Calculate Amount Paid in Taxes | Easy | |
| 1290 | Convert Binary Number in a Linked List to Integer | Easy | |
| 863 | All Nodes Distance K in Binary Tree | Medium | |
| 120 | Triangle | Medium | |
| 1249 | Minimum Remove to Make Valid Parentheses | Medium | |
| 713 | Subarray Product Less Than K | Medium | |
| 1944 | Number of Visible People in a Queue | Hard | |
| 2448 | Minimum Cost to Make Array Equal | Hard | |
| 133 | Clone Graph | Medium | |
| 7 | Reverse Integer | Medium | |
| 2008 | Maximum Earnings From Taxi | Medium | |
| 841 | Keys and Rooms | Medium | |
| 29 | Divide Two Integers | Medium | |
| 176 | Second Highest Salary | Medium | |
| 796 | Rotate String | Easy | |
| 130 | Surrounded Regions | Medium | |
| 135 | Candy | Hard | |
| 1190 | Reverse Substrings Between Each Pair of Parentheses | Medium | |
| 36 | Valid Sudoku | Medium | |
| 3366 | Minimum Array Sum | Medium | |
| 70 | Climbing Stairs | Easy | |
| 403 | Frog Jump | Hard | |
| 92 | Reverse Linked List II | Medium | |
| 2402 | Meeting Rooms III | Hard | |
| 1309 | Decrypt String from Alphabet to Integer Mapping | Easy | |
| 829 | Consecutive Numbers Sum | Hard | |
| 1254 | Number of Closed Islands | Medium | |
| 920 | Number of Music Playlists | Hard | |
| 366 | Find Leaves of Binary Tree | Medium | |
| 1169 | Invalid Transactions | Medium | |
| 2204 | Distance to a Cycle in Undirected Graph | Hard | |
| 752 | Open the Lock | Medium | |
| 129 | Sum Root to Leaf Numbers | Medium | |
| 10 | Regular Expression Matching | Hard | |
| 32 | Longest Valid Parentheses | Hard | |
| 37 | Sudoku Solver | Hard | |
| 39 | Combination Sum | Medium | |
| 45 | Jump Game II | Medium | |
| 57 | Insert Interval | Medium | |
| 68 | Text Justification | Hard | |
| 91 | Decode Ways | Medium | |
| 113 | Path Sum II | Medium | |
| 162 | Find Peak Element | Medium | |
| 189 | Rotate Array | Medium | |
| 226 | Invert Binary Tree | Easy | |
| 287 | Find the Duplicate Number | Medium | |
| 468 | Validate IP Address | Medium | |
| 19 | Remove Nth Node From End of List | Medium | |
| 622 | Design Circular Queue | Medium | |
| 844 | Backspace String Compare | Easy | |
| 973 | K Closest Points to Origin | Medium | |
| 992 | Subarrays with K Different Integers | Hard | |
| 1004 | Max Consecutive Ones III | Medium | |
| 1166 | Design File System | Medium | |
| 1347 | Minimum Number of Steps to Make Two Strings Anagram | Medium | |
| 1636 | Sort Array by Increasing Frequency | Easy | |
| 1046 | Last Stone Weight | Easy | |
| 1721 | Swapping Nodes in a Linked List | Medium | |
| 716 | Max Stack | Hard | |
| 704 | Binary Search | Easy | |
| 82 | Remove Duplicates from Sorted List II | Medium | |
| 1547 | Minimum Cost to Cut a Stick | Hard | |
| 410 | Split Array Largest Sum | Hard | |
| 407 | Trapping Rain Water II | Hard | |
| 78 | Subsets | Medium | |
| 166 | Fraction to Recurring Decimal | Medium | |
| 327 | Count of Range Sum | Hard | |
| 2208 | Minimum Operations to Halve Array Sum | Medium | |
| 1267 | Count Servers that Communicate | Medium | |
| 729 | My Calendar I | Medium | |
| 1079 | Letter Tile Possibilities | Medium | |
| 2592 | Maximize Greatness of an Array | Medium | |
| 142 | Linked List Cycle II | Medium | |
| 297 | Serialize and Deserialize Binary Tree | Hard | |
| 2226 | Maximum Candies Allocated to K Children | Medium | |
| 605 | Can Place Flowers | Easy | |
| 442 | Find All Duplicates in an Array | Medium | |
| 772 | Basic Calculator III | Hard | |
| 2622 | Cache With Time Limit | Medium | |
| 2127 | Maximum Employees to Be Invited to a Meeting | Hard | |
| 2055 | Plates Between Candles | Medium | |
| 203 | Remove Linked List Elements | Easy | |
| 321 | Create Maximum Number | Hard | |
| 339 | Nested List Weight Sum | Medium | |
| 38 | Count and Say | Medium | |
| 301 | Remove Invalid Parentheses | Hard | |
| 1824 | Minimum Sideway Jumps | Medium | |
| 368 | Largest Divisible Subset | Medium | |
| 212 | Word Search II | Hard | |
| 104 | Maximum Depth of Binary Tree | Easy | |
| 43 | Multiply Strings | Medium | |
| 311 | Sparse Matrix Multiplication | Medium | |
| 556 | Next Greater Element III | Medium | |
| 24 | Swap Nodes in Pairs | Medium | |
| 402 | Remove K Digits | Medium | |
| 2439 | Minimize Maximum of Array | Medium | |
| 1071 | Greatest Common Divisor of Strings | Easy | |
| 259 | 3Sum Smaller | Medium | |
| 1768 | Merge Strings Alternately | Easy | |
| 1248 | Count Number of Nice Subarrays | Medium | |
| 150 | Evaluate Reverse Polish Notation | Medium | |
| 2181 | Merge Nodes in Between Zeros | Medium | |
| 268 | Missing Number | Easy | |
| 271 | Encode and Decode Strings | Medium | |
| 1312 | Minimum Insertion Steps to Make a String Palindrome | Hard | |
| 211 | Design Add and Search Words Data Structure | Medium | |
| 545 | Boundary of Binary Tree | Medium | |
| 365 | Water and Jug Problem | Medium | |
| 1492 | The kth Factor of n | Medium | |
| 2047 | Number of Valid Words in a Sentence | Easy | |
| 1526 | Minimum Number of Increments on Subarrays to Form a Target Array | Hard | |
| 2603 | Collect Coins in a Tree | Hard | |
| 1539 | Kth Missing Positive Number | Easy | |
| 325 | Maximum Size Subarray Sum Equals k | Medium | |
| 445 | Add Two Numbers II | Medium | |
| 1095 | Find in Mountain Array | Hard | |
| 260 | Single Number III | Medium | |
| 84 | Largest Rectangle in Histogram | Hard | |
| 338 | Counting Bits | Easy | |
| 2422 | Merge Operations to Turn Array Into a Palindrome | Medium | |
| 2858 | Minimum Edge Reversals So Every Node Is Reachable | Hard | |
| 44 | Wildcard Matching | Hard | |
| 1481 | Least Number of Unique Integers after K Removals | Medium | |
| 107 | Binary Tree Level Order Traversal II | Medium | |
| 684 | Redundant Connection | Medium | |
| 1197 | Minimum Knight Moves | Medium | |
| 815 | Bus Routes | Hard | |
| 3650 | Minimum Cost Path with Edge Reversals | Medium | |
| 1488 | Avoid Flood in The City | Medium | |
| 202 | Happy Number | Easy | |
| 3680 | Generate Schedule | Medium | |
| 733 | Flood Fill | Easy | |
| 1633 | Percentage of Users Attended a Contest | Easy | |
| 25 | Reverse Nodes in k-Group | Hard | |
| 362 | Design Hit Counter | Medium | |
| 2043 | Simple Bank System | Medium | |
| 3203 | Find Minimum Diameter After Merging Two Trees | Hard | |
| 437 | Path Sum III | Medium | |
| 1193 | Monthly Transactions I | Medium | |
| 1057 | Campus Bikes | Medium |