1 | Three Sum To Zero | Arrays, Medium, Two Pointers |

110 | Set Matrix Zeroes | Arrays, Medium |

145 | Group Anagrams | Arrays, Medium |

161 | Longest Palindromic Substring | Medium, String, Two Pointers |

170 | Missing Ranges | Arrays, Medium |

176 | Increasing Triplet Subsequence | Arrays, Medium |

330 | Add Two LinkedList | Linked List, Medium |

382 | Odd-Even LinkedList | Linked List, Medium |

394 | Intersection of Two Linked Lists | Linked List, Medium |

449 | Binary Tree Inorder Traversal | Medium, Stack, Tree |

466 | Zigzag Traversal of Binary Tree | Breadth First Search, Medium, Tree |

474 | Binary Tree from Preorder and Inorder Traversal | Medium, Recursion, Tree |

481 | Kth Smallest Element in a BST | Depth First Search, Medium, Tree |

490 | Inorder Successor in BST | Medium, Tree |

644 | Inorder Predecessor In BST | Medium, Tree |

649 | Product of Array Except Self | Arrays, Hard |

658 | Number Of Islands | Depth First Search, Flood Fill, Medium |

666 | Spiral Matrix | Arrays, Hard, Recursion |

726 | Letter Combination of Telephone Numbers | Backtracking, Medium, Recursion |

729 | Generate Balanced Parentheses | Backtracking, Medium, Subsets |

745 | Permutations Of An Array (With Duplicate Sets) | Arrays, Backtracking, Medium, Subsets |

749 | Subsets Of An Array (With Duplicates Set) | Arrays, Backtracking, Medium, Subsets |

757 | Dutch National Flag | Arrays, Medium, Two Pointers |

759 | Top K Frequent Elements in Array | Arrays, Medium, TopK |

773 | Average of Contiguous Subarray of Size K | Arrays, Easy, Sliding Window |

777 | Maximum Subarray Sum of Size K | Arrays, Easy, Sliding Window |

780 | Smallest Contiguous Subarray with Sum S | Arrays, Medium, Sliding Window |

784 | Longest Substring with K Distinct Characters | Hard, Sliding Window, String |

796 | Fruit Into Basket | Arrays, Medium, Sliding Window |

801 | Longest Substring Without Repeating Characters | Medium, Sliding Window, String |

819 | Minimum Window Pattern Matching Substring | Hard, Sliding Window, String |

824 | Maximum from Subarray of Size K | Arrays, Medium, Sliding Window |

826 | Longest Repeating Character Substring after K Replacement | Arrays, Medium, Sliding Window |

832 | String Permutation Pattern Matching | Arrays, Medium, Sliding Window |

835 | Longest Subarray after replacing K Zero | Arrays, Medium, Sliding Window |

838 | Max Consecutive Ones in an Array | Arrays, Medium, Sliding Window |

840 | Intersection of Three Sorted Arrays | Arrays, Easy, Two Pointers |

844 | Squares of Sorted Array | Arrays, Easy, Two Pointers |

847 | Reverse an Array | Arrays, Easy, Two Pointers |

899 | Two Sum to Target | Arrays, Easy, Two Pointers |

901 | Intersection of Two Unsorted Arrays | Arrays, Easy, Two Pointers |

903 | Remove selected element from the array | Arrays, Easy, Two Pointers |

905 | Container With Most Water | Arrays, Medium, Two Pointers |

907 | Trapping Rain Water | Arrays, Hard, Two Pointers |

910 | Merge Sorted Array | Arrays, Easy, Two Pointers |

914 | Three Sum Closest to Target | Arrays, Medium, Two Pointers |

917 | Move All Zeroes to End of Array | Arrays, Easy, Two Pointers |

920 | Compare String with Backspace | Arrays, Easy, Two Pointers |

923 | Remove Duplicates from Sorted Array | Arrays, Easy, Two Pointers |

926 | Subarray Product Less Than K | Arrays, Medium, Sliding Window, Two Pointers |

943 | LinkedList Cycle | Fast And Slow, Linked List, Medium |

948 | Cycle in a Circular Array | Arrays, Fast And Slow, Medium |

952 | Happy Number | Arrays, Easy, Fast And Slow |

954 | Middle of the LinkedList | Arrays, Easy, Fast And Slow |

957 | Reorder LinkedList First and Last | Fast And Slow, Linked List, Medium |

964 | Validate Palindromic LinkedList | Easy, Fast And Slow, Linked List |

968 | Merge Overlapping Intervals | Medium, Merge Intervals |

973 | Insert Into Non-Overlapping Intervals | Hard, Merge Intervals |

975 | Find Interval Intersections | Medium, Merge Intervals |

982 | Conflicting Meetings | Easy, Medium, Merge Intervals |

986 | Minimum Meeting Rooms | Medium, Merge Intervals |

991 | Meeting Scheduler | Medium, Merge Intervals |

997 | Remove From Non-Overlapping Intervals | Medium, Merge Intervals |

999 | Employee Free Time From Busy Intervals | Hard, Merge Intervals |

1004 | Cyclic Array Sort | Arrays, Cyclic Sort, Easy |

1006 | Find Missing Number in Array | Arrays, Cyclic Sort, Easy |

1010 | Find All Missing Numbers in Array | Arrays, Cyclic Sort, Medium |

1015 | Find Duplicate Number in Array | Arrays, Cyclic Sort, Fast And Slow, Medium |

1020 | Find All Duplicates in Array | Arrays, Cyclic Sort, Medium |

1022 | Find First Missing Positive Number In Array | Arrays, Cyclic Sort, Hard |

1024 | Find Duplicate And Missing Number in Array | Arrays, Cyclic Sort, Hard |

1028 | Find First K Missing Positive Numbers in Array | Arrays, Cyclic Sort, Hard |

1037 | Topological Sort | Graph, Medium, Topological Sort |

1041 | Course Scheduling | Graph, Medium, Topological Sort |

1049 | Course Scheduling With Order | Graph, Medium, Topological Sort |

1053 | All Course Scheduling Orders | Graph, Hard, Topological Sort |

1062 | Course Scheduling In Preference Of Time | Dynamic Programming, Hard, Recursion |

1066 | Alien Dictionary | Graph, Hard, Topological Sort |

1070 | Sequence Reconstruction | Graph, Medium, Topological Sort |

1077 | Minimum Height Tree | Graph, Medium, Topological Sort |

1099 | Valid Parenthesis | Easy, Stack, String |

1102 | Next Permutation | Arrays, Two Pointers |

1113 | Permutation of Array (Removing Duplicate Sets) | Arrays, Backtracking, Medium, Subsets |

1116 | Level Order Traversal | Breadth First Search, Medium, Tree |

1120 | Lever Order Traversal From Leaf to Root | Breadth First Search, Medium, Tree |

1125 | Level Order Traversal With Level Average | Breadth First Search, Medium, Tree |

1129 | Vertical Order Traversal | Depth First Search, Medium, Tree |

1132 | Level Order Traversal of N-Ary Tree | Breadth First Search, Medium, Tree |

1135 | Binary Tree Traversal Using Stack | Medium, Stack, Tree |

1143 | Tree Traversal Using Recursion | Medium, Recursion, Tree |

1147 | Minimum Depth of Binary Tree | Breadth First Search, Medium, Tree |

1151 | Maximum Depth of Binary Tree | Breadth First Search, Depth First Search, Medium, Tree |

1157 | Right Side View Of Binary Tree | Breadth First Search, Medium, Tree |

1161 | Left Side View of Binary Tree | Breadth First Search, Medium, Tree |

1166 | Find Leaves of Binary Tree Until Tree Is Empty | Depth First Search, Medium, Tree |

1173 | Flood Fill | Depth First Search, Easy, Flood Fill |

1177 | Greatest Common Divisor Of Strings | Easy, Recursion, String |

1180 | Time Based Key-Value Store | Design, Hash Table, Medium |

1185 | Rank Team By Votes | Arrays, Medium |

1188 | Lemonade Change | Arrays, Easy |

1191 | Hit Counter | Design, Hash Table, Queue |

1195 | Logger Rate Limiter | Design, Easy, Queue |

1202 | Evaluate Expression in Reverse Polish Notation | Arrays, Easy, Stack |

1213 | HashMap in Java | Design, Hash Table, Linked List, Medium |

1221 | Design a Peeking Iterator | Design, Medium |

1224 | Leaves of Binary Tree From Left to Right | Depth First Search, Easy, Tree |

1227 | Leaf Similar Trees | Depth First Search, Medium, Tree |

1232 | Maximum Average of a Subtree | Depth First Search, Medium, Tree |

1235 | Binary Tree Iterator (Inorder) | Binary Search Tree, Design, Medium, Stack |

1242 | Total Number of Friend Circle | Breadth First Search, Depth First Search, Medium |

1252 | What is a Graph | Graph |

1262 | Undirected Graph Using Adjacency List | Easy, Graph |

1269 | Directed Graph using Adjacency List | Easy, Graph |

1279 | Undirected Graph using Adjacency Matrix | Easy, Graph |

1281 | Directed Graph using Adjacency Matrix | Easy, Graph |

1306 | BFS Traversal Of Undirected Graph using Adjacency List | Breadth First Search, Graph, Medium |

1309 | BFS Traversal of Directed Graph using Adjacency List | Breadth First Search, Graph, Medium |

1312 | DFS Traversal Of Undirected Graph using Adjacency List | Depth First Search, Graph, Medium |

1315 | DFS Traversal Of Directed Graph using Adjacency List | Depth First Search, Graph, Medium |

1324 | BFS Traversal Of Undirected Graph using Adjacency Matrix | Breadth First Search, Graph, Medium |

1329 | BFS Traversal Of Directed Graph using Adjacency Matrix | Breadth First Search, Graph, Medium |

1337 | DFS Traversal Of Undirected Graph using Adjacency Matrix | Depth First Search, Graph, Medium |

1339 | DFS Traversal Of Directed Graph using Adjacency Matrix | Depth First Search, Graph, Medium |

1345 | Number of Connected Components in an Undirected Graph | Breadth First Search, Graph, Medium |

1356 | Object-Oriented Programming And Concepts | Design |

1375 | Java Common Concepts | Design |

1388 | Collection Framework in Java | Design |

1399 | Reverse a LinkedList | Easy, Linked List |

1401 | Reverse a Sub List from LinkedList | Linked List, Medium |

1403 | Reverse Every K Sized Sub List | Hard, Linked List |

1408 | Reverse Every K Sized Sub List Except Last | Hard, Linked List |

1412 | Delete Node in a LinkedList | Easy, Linked List |

1414 | Remove All Nodes With Given Value From LinkedList | Easy, Linked List |

1417 | Remove Alternating K Elements From LinkedList | Hard, Linked List |

1421 | Find Maximum Overlapping Interval and Overlapping Point | Medium, Merge Intervals |

1427 | Iterator in Java | Design |

1432 | Quick Sort Algorithm | Arrays, Easy, Sorting |

1435 | Kth Largest Element in an Array | Arrays, Medium, TopK |

1437 | Median of an Unsorted Array | Arrays, Medium |

1439 | Consistent Hashing in Java | Design, Hash Table |

1443 | Iterable in Java | Design |

1450 | ArrayList in Java | Arrays, Design |

1455 | LinkedList in Java | Design, Linked List |

1458 | Stack in Java | Design, Stack |

1462 | PriorityQueue in Java | Design, Queue |

1464 | HashSet in Java | Arrays, Design |

1466 | TreeSet in Java | Design |

1470 | LinkedHashSet in Java | Design |

1483 | Vector In Java | Design |

1502 | Pass By Value and Pass By Reference | Design |

1507 | Java Memory Model and Garbage Collection | Design |

1514 | Find Median from Continuous Data Stream | Design, Hard, Two Heaps |

1521 | Sliding Window Median | Hard, Sliding Window, Two Heaps |

1526 | Moving Average from Data Stream | Easy, Sliding Window |

1529 | Validate Next Interval | Hard, Two Heaps |

1534 | Top K Largest Elements in Array | Arrays, Medium, TopK |

1537 | Kth Smallest Element in an Array | Arrays, Medium, TopK |

1544 | K Closest Points to Origin | Medium, TopK |

1551 | Complexity Cheat Sheet | Design, Medium |

1559 | Sort Characters By Frequency | Medium, String, TopK |

1564 | Find K Closest Elements to X in an Array | Binary Search, TopK, Two Pointers |

1567 | Rearrange String | Medium, String, TopK |

1576 | Rearrange String k Distance Apart | Hard, String, TopK |

1578 | Task Scheduler | Arrays, Hard, TopK |

1582 | Maximum Frequency Stack | Design, Hard, Stack, TopK |

1597 | Subset of an Array (Removing Duplicate Sets) | Arrays, Backtracking, Medium, Subsets |

1619 | Letter Case Permutation | Medium, String, Subsets |

1627 | Combination Sum | Arrays, Medium, Subsets |

1631 | Combination Sum without Duplicates | Arrays, Medium, Subsets |

1647 | Evaluate All Answers For Expression | Dynamic Programming, Hard, Subsets |

1651 | Introduction to Threads | Design, Thread |

1660 | Multithreading in Java | Design, Thread |

1662 | Synchronized in Java | Design, Thread |

1667 | How To Create Thread In Java | Design, Thread |

2035 | Web Application : Basic Concepts | Design |

2078 | Object Pool Design Pattern | Design |

2099 | Shortest Distance to a Character | Easy, String |

2109 | Frequency Count of All Possible Item Sets | Hard, Hash Table, Subsets |

2129 | Queue in Java | Linked List, Medium, Queue |

2135 | LinkedHashMap in Java | Design, Hash Table, Medium |

2140 | Skyline Problem | Arrays, Hard, Merge Intervals |

2149 | Single Element in a Sorted Array | Arrays, Binary Search, Medium |

2154 | Level Order Successor in Binary Tree | Breadth First Search, Easy, Tree |

2156 | Connect Level Order Siblings | Breadth First Search, Medium, Tree |

2159 | Connect All Level Order Siblings in Binary Tree | Breadth First Search, Medium, Tree |

2179 | Find Path (Root to Leaf) With Sum In Binary Tree | Depth First Search, Easy, Tree |

2181 | All Path Sum for Binary Tree | Depth First Search, Medium, Tree |

2184 | Count Total Paths For Sum in Binary Tree | Depth First Search, Medium, Tree |

2187 | Breadth First Search Traversal of Binary Tree | Breadth First Search, Easy, Tree |

2190 | Depth First Search Traversal of Binary Tree | Depth First Search, Easy, Tree |

2193 | All Paths From Root to Leaf in Binary Tree | Depth First Search, Medium, Tree |

2196 | Path With Given Sequence | Depth First Search, Medium, Tree |

2199 | Diameter of Binary Tree (Longest path between any Two Nodes) | Depth First Search, Medium, Tree |

2202 | 0-1 Knapsack Problem | Dynamic Programming, Hard |

2206 | Find Subset With Sum | Dynamic Programming, Medium |

2213 | Binary Search | Binary Search, Easy |

2218 | Search in a Sorted Array of Unknown Size | Binary Search, Medium |

2220 | Peak Index in Mountain Array | Binary Search, Easy |

2223 | Magic Index or Fixed Point in Array | Binary Search, Easy |

2226 | Binary Search with Order-Agnostic Array | Binary Search, Easy |

2230 | Largest Element Smaller than Target in Array | Binary Search, Medium |

2233 | Smallest Element Greater than Target in Array | Binary Search, Medium |

2235 | Find Smallest Letter Greater Than Target in Array | Binary Search, Medium |

2242 | Find First and Last Position of Element in Sorted Array | Binary Search, Medium |

2248 | Closest Element in Array | Binary Search, Medium |

2257 | Search in Mountain Array | Binary Search Tree, Medium |

2260 | Search in Circular Array (Rotated Sorted Array) | Binary Search, Medium |

2264 | Equal Subset Sum Partition | Dynamic Programming, Medium |

2268 | Count subsets with sum equal to X | Dynamic Programming, Medium |

2271 | Unbounded Knapsack | Dynamic Programming, Medium |

2273 | Rotate Array by K Steps | Arrays, Easy |

2275 | Search a 2D Matrix | Arrays, Binary Search, Medium |

2278 | Merge K Sorted Lists | Hard, K Way Merge |

2286 | Kth Smallest Element in M Arrays | Hard, K Way Merge |

2291 | Kth Smallest Element in Sorted Matrix | Binary Search, Hard, K Way Merge |

2300 | Smallest Range Covering Elements from K Lists | Hard, K Way Merge |

2303 | Find Median in M Sorted Array | Hard, K Way Merge |

2305 | Median of Two Sorted Arrays | Binary Search, Hard |

2320 | REST API : Basics and How to Use it | Design |

2341 | N-ary Tree Traversal | Depth First Search, Easy, Tree |

2347 | Maximum Depth of N-ary Tree | Breadth First Search, Depth First Search, Easy, Tree |

2351 | Encode N-ary Tree to Binary Tree | Depth First Search, Hard, Tree |

2363 | Serialize and Deserialize N-ary Tree | Depth First Search, Hard, Tree |

2368 | Serialize Deserialize a Binary Tree | Depth First Search, Hard, Tree |

2381 | Relative Sort Array | Arrays, Easy |

2388 | Custom Sort String | Arrays, Medium |

2398 | Maximize Capital | Hard, Two Heaps |

2403 | Find Next Right Interval | Hard, Two Heaps |

2410 | LRU Cache | Design, Medium |

2417 | LFU Cache | Design, Hard |

2425 | ConcurrentHashMap in Java | Design, Hard |

2442 | Sort HashMap by Value | Easy, Hash Table |

2447 | Coin Change Count Min Coins | Dynamic Programming, Medium |

2453 | Coin Change Count Total Ways | Dynamic Programming, Medium |

2460 | Coin Change Count Max Coins | Dynamic Programming, Medium |

2467 | Fibonacci Number | Dynamic Programming, Easy |

2470 | Merge Sort | Arrays, Easy, Sorting |

2478 | External Sorting | Design, Hard, Sorting |

2594 | System Design Youtube | Design |

2602 | Quad Tree | Depth First Search, Flood Fill, Hard, Tree |

2614 | Lowest Common Ancestor of Binary Tree | Depth First Search, Medium, Tree |

2655 | Check Completeness of Binary Tree | Breadth First Search, Medium, Tree |

2700 | Perfect Rectangle Cover | Hard |

2706 | Maximum Sum of Two Non-Overlapping Subarrays | Arrays, Medium |

2722 | Word Search in Matrix | Backtracking, Depth First Search, Flood Fill, Medium |

2727 | All Words Search In Matrix – Boggler Problem | Backtracking, Depth First Search, Flood Fill, Hard, Trie |

2733 | Trie or Prefix Tree | Medium, Tree, Trie |

2741 | Snakes and Ladders | Backtracking, Breadth First Search, Medium |

2800 | Flatten Nested List Iterator | Design |

2809 | Word Break Problem | Dynamic Programming, Medium, Recursion |

2813 | Word Break – Find All Words | Dynamic Programming, Hard, Recursion |

2835 | Design Tic Tac Toe | Arrays, Design, Medium |

2851 | Abstract Factory Design Pattern | Design |

2858 | Builder Pattern | Design |

2869 | Prototype Design Pattern | Design |

2876 | Singleton Design Pattern | Design |

2895 | Application Tiers | Design |

2903 | Principles | Design |

2909 | Client Server Architecture | Design |

2913 | SOAP and REST | Design |

2922 | HTTP Push and HTTP Pull Mechanism | Design |

2940 | Scalability | Design |

2949 | Latency | Design |

2958 | Availability | Design |

2965 | CAP Theorem | Design |

2971 | Proxy Server | Design |

2976 | Load Balancer | Design |

2983 | What happens when user types URL in the Browser | Design |

2993 | Caching | Design |

3002 | Relational and Non Relational Database | Design |

3008 | ACID vs BASE Property | Design |

3010 | Database Consistency Patterns | Design |

3016 | Database Sharding or Partitioning | Design |

3025 | Types of NOSQL Database | Design |

3053 | How HTTPS Works? | Design, Hard |

3091 | Vertical Order Traversal sorted by Level and Value | Depth First Search, Hard, Tree |

3095 | Decode Ways | Dynamic Programming, Hard |

3111 | Verify in Alien Dictionary | Easy, String |

3114 | Minimum Remove to make Valid Parenthesis in String | Medium, Stack |

3116 | Count Total Consecutive Subarray Whose Sum Equals K | Arrays, Hash Table, Medium |

3119 | Validate Palindrome by Removing One Character | Easy, String, Two Pointers |

3124 | Leftmost Column with at Least a One | Arrays, Medium |

3129 | Add Strings of Integer | Easy, Numbers |

3138 | Design Add and Search Words Data Structure | Design, Medium |

3144 | Minimum Remove to make Valid Parenthesis (Get All Combination) | Backtracking, Hard, String |

3155 | Range Sum of Binary Search Tree | Binary Search Tree, Depth First Search, Easy |

3158 | All String Anagram Pattern Matching | Medium, Sliding Window |

3161 | Binary Tree Maximum Path Sum (Any Start to End) | Depth First Search, Tree |

3164 | Expression Operators Combination to Get Target | Backtracking, Hard, Subsets |

3167 | Validate String Palindrome Skipping Special Characters | Easy, Two Pointers |

3174 | Random Index Pick with Weight | Binary Search, Medium, Random |

3188 | Architecture Options for Multiple Datacenter | Design |

3195 | Insert Delete GetRandom O(1) – With Duplicates | Design |

3200 | Insert Delete GetRandom O(1) – Without Duplicates | Design, Medium |

3206 | Flatten Binary Tree to Linked List | Depth First Search, Medium, Tree |

3214 | Decode Ways With Special Character | Dynamic Programming, Hard |

3221 | Largest SubMatrix with All Border 1 | Arrays, Medium |

3224 | Regular Expression Wildcard Pattern Matching | Dynamic Programming, Hard |

3229 | Remove Comments from String of Code | Easy, String |

3246 | All Nodes at k Distance from Target Node | Breadth First Search, Depth First Search, Medium, Tree |

3250 | Combinations | Medium, Subsets |

3270 | Design Circular Queue (RingBuffer) | Design, Medium |

3272 | Design Circular Deque | Design, Medium |

3289 | Longest Increasing Subsequence | Dynamic Programming, Medium |

3295 | Partition a LinkedList by Target | Linked List, Medium |

3298 | String Compression | Medium, Sliding Window |

3302 | Repeated DNA Sequences | Medium, Sliding Window |

3304 | Largest Square Submatrix With All 1 | Dynamic Programming, Medium |

3310 | Remove Duplicates And Original From Sorted LinkedList | Linked List, Medium, Two Pointers |

3317 | Search in Circular Array With Duplicates | Binary Search, Medium |

3322 | Four Sum | Medium, Two Pointers |

3333 | Word Ladder | Depth First Search, Medium |

3337 | Gas Station or Petrol Filling Problem | Arrays, Medium |

3352 | Introduction to Union Find or Disjoint Set | Union Find |

3379 | Cycle in Undirected Graph Using Disjoint Set | Graph, Union Find |

3384 | Cycle in Graph Using Union By Rank with Path Compression | Graph, Union Find |

3391 | Find if A is Friend of B | Union Find |

3399 | Earliest Time When All are Friends | Medium, Union Find |

3409 | Shortest Distance from All Building in Grid | Breadth First Search, Hard |

3416 | Find K Pairs with Smallest Sums | Arrays, Medium |

3424 | Maximum Subarray Sum | Easy, Sliding Window |

3434 | Max Value Stack | Design, Medium, Stack |

3441 | Can Place Neighboring 1’s in Array | Arrays, Easy |

3460 | Min Value Stack | Design, Easy |

3463 | Design Bounded Blocking Queue | Design, Medium |

3479 | Shuffle an Array | Arrays, Medium |

3487 | Nim Game | Backtracking, Easy, minimax |

3501 | Flip Game | Easy, minimax |

3505 | Predict the Winner | Dynamic Programming, Medium, minimax |

3515 | 100 Game – Without Reusing Integers | Dynamic Programming, Medium, minimax |

3520 | Climbing Stairs | Dynamic Programming, Easy |

3532 | HTTP Attacks | Design, Hard |

3544 | Operating System in Nutshell | Design, Hard |

3568 | Computer Networks in Nutshell | Design |

3594 | Design RESTful Shopping Cart | Design, Hard, System Design |

3623 | Continuous Subarray Sum | Arrays, Medium |

3627 | Max Area Of A Island | Depth First Search, Flood Fill |

3629 | Design Browser History | Design, Hard |

3641 | Nested List Weight Sum | Design, Easy |

3647 | How to make a Service Scalable? | Design, Hard |

3664 | Distributed Transactions | Design, Hard |

3690 | Divide Two Integers | Medium, Numbers |

3705 | Power Of X | Easy, Numbers |

3711 | Validate Decimal String | Hard, Numbers |

3717 | Add Binary String | Bitwise, Easy |

3721 | Clone Graph (Deep Copy Graph) | Graph, Medium |

3752 | Find Closest Node in BST | Binary Search Tree, Easy |

3776 | Random Variables | Easy, Random |

3785 | Randomized Algorithm | Easy, Random |

3791 | Binomial Random Variables | Easy, Random |

3797 | Implement Random7 Using Random5 | Medium, Random |

3812 | Implement Random10 Using Random 7 | Easy, Random |

3817 | Shuffle a Given Array or Deck Of Cards | Medium, Random |

3826 | Reservoir Sampling | Easy, Random |

3832 | Random Number From Stream | Medium, Random |

3838 | Random Pick Index | Medium, Random |

3849 | Convert BST To Sorted Doubly Linked List | |

3902 | Domain Name System | Design, Medium |

3917 | Content Distribution Network (CDN) | Design, Medium |

3928 | Asynchronism | Design, Medium |

3937 | Tweet Counts Per Frequency | Design, Hash Table, Medium |

3949 | Maximum One Swap For Max Valued Number | |

3962 | Insert Value in Sorted Circular LinkedList | Linked List, Medium |

3970 | Insert Value in Sorted LinkedList | Linked List, Medium |

3980 | Accounts Merge | Medium, Union Find |

4026 | Design Instagram (Photo Sharing Social Network) | Design, System Design |

4083 | Copy LinkedList with Random Pointer | Linked List, Medium |

4089 | Validate Binary Search Tree | Binary Search Tree, Easy |

4092 | Remove K Consecutive Characters | Medium, Stack, String |

4108 | Lexicographically Smallest String From Root To Leaf in Binary Tree | Depth First Search, Medium |

4127 | Is Graph Bipartite ? | Graph, Medium |

4162 | Design Web Crawler | Design, Medium, System Design |

4189 | Design Twitter | Design, Hard, System Design |

4368 | Design Kubernates (Application Deployment Management System) | Design, Hard, System Design |

4419 | Design Twitter (User Tweet Feed And Follow) | Design, Medium |

4441 | Making A Large Island (Replacing/Swapping One Zero with One) | Flood Fill, Hard |

4473 | Total Subsequence with Min and Max Less Than Target | Medium, Two Pointers |

4544 | Shortest Palindrome By Adding Character | Hard, String |

4551 | Design Autocomplete System | Design, Hard, System Design |

4642 | Wildcard Pattern Matching | |

4657 | Dot Product of Two Sparse Vectors | Arrays, Medium |

4694 | Distributed Ledger Technology (Blockchain) | |

4845 | Design WhatsApp | Design, Hard, System Design |

4855 | Deciding Best Storage Solution | Design, Hard, System Design |

4954 | Group All Shifted String Together | Arrays, Medium |

4962 | Merging Iterator | Design, Hard |

5007 | Average of Each Subtree Excluding Node | Depth First Search, Medium |

5015 | Group Duplicate File In System | Arrays, Medium |

5026 | Wrap Sentence in Limit Length (Word Wrap) | Hard |

5034 | Basic Calculator | Medium, Numbers |

5038 | Basic Calculator (Including Parenthesis) | Hard, Numbers |

5050 | Design Google Maps | Design, Hard, System Design |

5062 | Delete Given Node From LinkedList | Easy, Linked List |

5079 | Largest BST Subtree in Binary Tree | Binary Search Tree, Depth First Search |

5084 | Friends Of Appropriate Ages (Count Friend Request) | Arrays, Medium |

5106 | Absolute Path to Canonical Path | Medium, String |

5119 | Cracking the Safe | |

5128 | De Bruijn Sequence (Inverse Burrows Wheeler Transform) | Hard, String |

5132 | Hash Table Using Chaining | Design, Hash Table, Medium |

5144 | Binary Tree Iterator II (Inorder) | Binary Search Tree, Design, Medium |

5149 | Maximum Sum of Three Non Overlapping Subarrays | Arrays, Dynamic Programming, Hard |

5153 | Minimum Stickers to Generate Word | Dynamic Programming, Hard |

5160 | Natural Sorting Comparator | Design, Hard |

5165 | Balance a Binary Search Tree | Binary Search Tree, Medium |

5189 | Design Uber | Design, Hard, System Design |

5203 | Design Dropbox | Design, Hard, System Design |

5233 | Design Twitter Search | |

5258 | Design Leaderboard | Design, Hard, System Design |

5292 | Design Google Ads | Design, Hard, System Design |

5334 | Lowest Common Ancestor in Undirected Graph | Graph, Hard |

5369 | Design Google Translate | Design, Hard, System Design |

5436 | Design Yelp | Design, Hard, System Design |