| 1 |
|
|
|
|
| 2 |
medium
|
959. Regions Cut By Slashes |
DFS, BFS, Union Find, Array, Hash Table, Matrix, AMateList |
DFS with memoization |
| 3 |
medium
|
885. Spiral Matrix III |
Array, Matrix, Simulation, AMateList |
|
| 4 |
medium
|
791. Custom Sort String |
Hash Table, String, Sorting, AMateList, Two Pointers |
|
| 5 |
medium
|
708. Insert into a Sorted Circular Linked List |
Linked List, AMateList |
|
| 6 |
medium
|
7. Reverse Integer |
Math |
|
| 7 |
medium
|
560. Subarray Sum Equals K |
Array, Hash Table, Prefix Sum, AMateList |
|
| 8 |
hard
|
42. Trapping Rain Water |
Stack, Array, Two Pointers, DP, Monotonic Stack, AMateList |
|
| 9 |
easy
|
415. Add Strings |
Math, String, Simulation, AMateList, Two Pointers |
|
| 10 |
hard
|
4. Median of Two Sorted Arrays |
Array, Binary Search, Divide and Conquer, AMateList |
|
| 11 |
medium
|
394. Decode String |
Stack, Recursion, String, AMateList |
|
| 12 |
medium
|
348. Design Tic-Tac-Toe |
Design, Array, Hash Table, Matrix, Simulation, AMateList |
|
| 13 |
medium
|
34. Find First and Last Position of Element in Sorted Array |
Array, Binary Search, BS |
|
| 14 |
medium
|
339. Nested List Weight Sum |
DFS, BFS |
|
| 15 |
medium
|
333. Largest BST Subtree |
Tree, DFS, BFS, DP, Binary Tree, AMateList |
|
| 16 |
hard
|
273. Integer to English Words |
Recursion, Math, String |
|
| 17 |
easy
|
219. Contains Duplicate II |
Array, Hash Table, Sliding Window, AMateList |
|
| 18 |
medium
|
2. Add Two Numbers |
Recursion, Linked List, Math |
|
| 19 |
medium
|
1868. Product of Two Run-Length Encoded Arrays |
Array, Two Pointers, AMateList |
|
| 20 |
easy
|
1768. Merge Strings Alternately |
Two Pointers, String, AMateList |
|
| 21 |
easy
|
17. Letter Combinations of a Phone Number |
Hash Table, String, Backtacking, AMateList |
|
| 22 |
medium
|
1570. Dot Product of Two Sparse Vectors |
Design, Array, Hash Table, Two Pointers, AMateList |
|
| 23 |
medium
|
11. Container With Most Water |
Greedy, Array, Two Pointers, AMateList |
|
| 24 |
medium
|
1091. Shortest Path in Binary Matrix |
Array, BFS, Matrix, AMateList |
|
| 25 |
easy
|
989. Add to Array-Form of Integer |
Array, Math |
|
| 26 |
easy
|
977. Squares of a Sorted Array |
Array, Two Pointers, Sorting |
|
| 27 |
easy
|
973. K Closest Points to Origin |
Geometry, Array, Math, Divide and Conquer, Quickselect, Sorting, Heap |
|
| 28 |
easy
|
938. Range Sum of BST |
Tre, DFS, BFS, BT |
|
| 29 |
easy
|
88. Merge Sorted Array |
Array, Two Pointers, Sorting, Binary Search |
|
| 30 |
medium
|
785. Is Graph Bipartite? |
DFS, BFS, Union Find, Graph |
|
| 31 |
medium
|
784. Letter Case Permutation |
Bit Manipulation, String, Backtracking |
|
| 32 |
hard
|
778. Swim in Rising Water |
DFS, BFS, Union Find, Array, Binary Search, Matrix, Heap |
|
| 33 |
medium
|
673. Number of Longest Increasing Subsequence |
Binary indexed Tree, Segment Tree, Array, DP |
|
| 34 |
easy
|
637. Average of Levels in Binary Tree |
Tree, DFS, BFS, BT |
|
| 35 |
easy
|
461. Hamming Distance |
Bit Manipulation |
|
| 36 |
easy
|
257. Binary Tree Paths |
Tree, DFS, String, Backtracking, BT |
|
| 37 |
easy
|
1379. Find a Corresponding Node of a Binary Tree in a Clone of That Tree |
Tree, DFS, BFS, BT |
|
| 38 |
medium
|
1249. Minimum Remove to Make Valid Parentheses |
Stack, String, stack |
|
| 39 |
medium
|
1778. Shortest Path in a Hidden Grid |
DFS, BFS, Graph, Interactive, AMateList |
|
| 40 |
medium
|
1778. Shortest Path in a Hidden Grid |
DFS, BFS, Graph, Interactive, AMateList |
|
| 41 |
medium
|
1778. Shortest Path in a Hidden Grid |
DFS, BFS, Graph, Interactive, AMateList |
|
| 42 |
medium
|
1778. Shortest Path in a Hidden Grid |
DFS, BFS, Graph, Interactive, AMateList |
|
| 43 |
medium
|
1778. Shortest Path in a Hidden Grid |
DFS, BFS, Graph, Interactive, AMateList |
|
| 44 |
medium
|
1778. Shortest Path in a Hidden Grid |
DFS, BFS, Graph, Interactive, AMateList |
|
| 45 |
medium
|
1778. Shortest Path in a Hidden Grid |
DFS, BFS, Graph, Interactive, AMateList |
|
| 46 |
medium
|
1778. Shortest Path in a Hidden Grid |
DFS, BFS, Graph, Interactive, AMateList |
|
| 47 |
medium
|
1778. Shortest Path in a Hidden Grid |
DFS, BFS, Graph, Interactive, AMateList |
|
| 48 |
medium
|
1778. Shortest Path in a Hidden Grid |
DFS, BFS, Graph, Interactive, AMateList |
|
| 49 |
medium
|
1778. Shortest Path in a Hidden Grid |
DFS, BFS, Graph, Interactive, AMateList |
|
| 50 |
medium
|
1778. Shortest Path in a Hidden Grid |
DFS, BFS, Graph, Interactive, AMateList |
|
| 51 |
medium
|
764. Largest Plus Sign |
Array, DP, AMateList |
|
| 52 |
medium
|
1778. Shortest Path in a Hidden Grid |
DFS, BFS, Graph, Interactive, AMateList |
|
| 53 |
medium
|
1773. Count Items Matching a Rule |
Array, String, AMateList |
|
| 54 |
medium
|
1762. Buildings With an Ocean View |
Stack, Array, Monotonic Stack, AMateList |
|
| 55 |
medium
|
1748. Sum of Unique Elements |
Array, Hash Table, Counting, AMateList |
|
| 56 |
medium
|
1718. Construct the Lexicographically Largest Valid Sequence |
Array, Backtracking, AMateList |
|
| 57 |
medium
|
1650. Lowest Common Ancestor of a Binary Tree III |
Tree, Hash Table, Two Pointers, BT, AMateList, Stack |
|
| 58 |
medium
|
1586. Binary Search Tree Iterator II |
Stack, Tree, Design, BST, BT, Iterator, AMateList |
|
| 59 |
medium
|
1522. Diameter of N-Ary Tree |
Tree, DFS, AMateList |
|
| 60 |
medium
|
1460. Make Two Arrays Equal by Reversing Subarrays |
Array, Hash Table, Sorting, AMateList |
|
| 61 |
medium
|
1357. Apply Discount Every n Orders |
Design, Array, Hash Table, AMateList |
|
| 62 |
medium
|
1242. Web Crawler Multithreaded |
Array, DP, AMateList |
|
| 63 |
easy
|
3095. Shortest Subarray With OR at Least K I |
Bit Manipulation, Array, Sliding Window, AMateList |
|
| 64 |
easy
|
2824. Count Pairs Whose Sum is Less than Target |
Array, Two Pointers, Binary Search, Sorting, AMateList |
|
| 65 |
easy
|
2553. Separate the Digits in an Array |
Array, Two Pointers, Binary Search, Sorting, AMateList |
|
| 66 |
easy
|
1242. Web Crawler Multithreaded |
Array, DP, AMateList |
|
| 67 |
easy
|
2210. Count Hills and Valleys in an Array |
Array, AMateList, Math |
|
| 68 |
easy
|
21. Merge Two Sorted Lists |
Recursion, Linked List, AMateList |
|
| 69 |
easy
|
1920. Build Array from Permutation |
Array, Simulation, AMateList |
|
| 70 |
easy
|
1826. Faulty Sensor |
Array, Two Pointers, AMateList |
|
| 71 |
medium
|
1810. Minimum Path Cost in a Hidden Grid |
DFS, BFS, Graph, Interactive, Heap, AMateList |
|
| 72 |
medium
|
1790. Check if One String Swap Can Make Strings Equal |
Hash Table, String, Counting, AMateList |
|
| 73 |
medium
|
1443. Minimum Time to Collect All Apples in a Tree |
Tree, DFS, BFS, Hash Table, AMateList |
|
| 74 |
medium
|
1361. Validate Binary Tree Nodes |
Tree, DFS, BFS, Union Find, Graph, Binary Tree, AMateList |
|
| 75 |
medium
|
1236. Web Crawler |
DFS, BFS, String, Interactive, AMateList |
|
| 76 |
medium
|
1043. Partition Array for Maximum Sum |
Array, DP, AMateList |
|
| 77 |
medium
|
1040. Moving Stones Until Consecutive II |
Array, Math, Two Pointers, Sorting, AMateList |
|
| 78 |
medium
|
1428. Leftmost Column with at Least a One |
Array, BS, Interactive, Matrix, AMateList, Binary Search |
|
| 79 |
medium
|
998. Maximum Binary Tree II |
Tree, BT, AMateList, Binary Search |
|
| 80 |
medium
|
1123. Lowest Common Ancestor of Deepest Leaves |
Tree, DFS, BFS, Hash Table, BT, AMateList |
|
| 81 |
medium
|
1033. Moving Stones Until Consecutive |
brainteaser, Math, AMateList |
|
| 82 |
medium
|
1004. Max Consecutive Ones III |
Array, BS, Prefix Sum, Sliding Window, AMateList |
|
| 83 |
medium
|
958. Check Completeness of a Binary Tree |
Tree, BFS, Binary Tree, AMateList |
|
| 84 |
easy
|
896. Monotonic Array |
Array, AMateList |
|
| 85 |
medium
|
893. Groups of Special-Equivalent Strings |
Array, Hash Table, String, Sorting, AMateList |
|
| 86 |
medium
|
825. Friends Of Appropriate Ages |
Array, Two Pointers, Binary Search, Sorting, AMateList |
|
| 87 |
easy
|
1213. Intersection of Three Sorted Arrays |
Array, Hash Table, Binary Search, Counting, AMateList |
|
| 88 |
easy
|
1108. Defanging an IP Address |
String, AMateList |
|
| 89 |
medium
|
426. Convert Binary Search Tree to Sorted Doubly Linked List |
Stack, Tree, DFS, BST, Linked List, BT, Doubly-Linked List, AMateList |
|
| 90 |
medium
|
750. Number Of Corner Rectangles |
Array, Math, DP, Matix, AMateList |
|
| 91 |
easy
|
703. Kth Largest Element in a Stream |
Bit Manipulation, Array, Math, AMateList |
|
| 92 |
easy
|
680. Valid Palindrome II |
Greedy, Two Pointers, String, AMateList |
|
| 93 |
easy
|
674. Longest Continuous Increasing Subsequence |
Array, AMateList |
|
| 94 |
medium
|
670. Maximum Swap |
Greedy, Math, AMateList |
|
| 95 |
medium
|
653. Two Sum IV - Input is a BST |
Tree, DFS, BFS, BST, Hash Table, Two Pointers, BT, AMateList |
|
| 96 |
medium
|
477. Total Hamming Distance |
Bit Manipulation, Array, Math, AMateList |
|
| 97 |
medium
|
398. Random Pick Index |
Reservoir Sampling, Hash Table, Math, Randomized, AMateList |
|
| 98 |
easy
|
674. Longest Continuous Increasing Subsequence |
Array, AMateList |
|
| 99 |
medium
|
636. Exclusive Time of Functions |
Stack, Array, AMateList |
|
| 100 |
easy
|
572. Subtree of Another Tree |
Tree, DFS, Binary Tree, String Matching, Hash Function, AMateList |
|
| 101 |
medium
|
535. Encode and Decode TinyURL |
Design, Hash Table, String, Hash Function, AMateList |
|
| 102 |
medium
|
523. Continuous Subarray Sum |
Array, Hash Table, Math, Prefix Sum, AMateList |
|
| 103 |
medium
|
494. Target Sum |
Array, DP, Backtracking, AMateList |
|
| 104 |
medium
|
341. Flatten Nested List Iterator |
Stack, Tree, DFS, Design, Queue, Iterator, AMateList |
|
| 105 |
medium
|
325. Maximum Size Subarray Sum Equals k |
Array, Hash Table, Prefix Sum, AMateList |
|
| 106 |
medium
|
311. Sparse Matrix Multiplication |
Array, Hash Table, Matrix, AMateList |
|
| 107 |
medium
|
286. Walls and Gates |
BFS, Array, Matrix, AMateList |
|
| 108 |
medium
|
285. Inorder Successor in BST |
Tree, DFS, BFS, Binary Tree, AMateList |
|
| 109 |
medium
|
554. Brick Wall |
Array, Hash Table, AMateList |
|
| 110 |
medium
|
277. Find the Celebrity |
Graph, Two Pointers, Interactive, AMateList |
|
| 111 |
medium
|
261. Graph Valid Tree |
DFS, BFS, Union Find, Graph, AMateList |
|
| 112 |
medium
|
253. Meeting Rooms II |
Greedy, Array, Two Pointers, Prefix Sum, Sorting, Heap, AMateList |
|
| 113 |
easy
|
252. Meeting Rooms |
Array, Sorting, AMateList |
|
| 114 |
easy
|
234. Palindrome Linked List |
Stack, Recursion, Linked List, Two Pointers, AMateList |
|
| 115 |
medium
|
215. Kth Largest Element in an Array |
Array, Divide and Conquer, Quickselect, Sorting, Heap(Priority Queue), AMateList |
|
| 116 |
medium
|
168. Excel Sheet Column Title |
Math, String, AMateList |
|
| 117 |
medium
|
69. Sqrt(x) |
Math, Binary Search, AMateList |
|
| 118 |
medium
|
43. Multiply Strings |
Math, String, Simulation, AMateList |
|
| 119 |
medium
|
161. One Edit Distance |
Two Pointers, String, AMateList |
|
| 120 |
easy
|
157. Read N Characters Given Read4 |
Array, Interactive, Simulation, AMateList |
|
| 121 |
medium
|
146. LRU Cache |
Design, Hash Table, Linked List, Double Linked List, AMateList |
|
| 122 |
medium
|
128. Longest Consecutive Sequence |
Union Find, Array, Hash Table, AMateList |
|
| 123 |
medium
|
102. Binary Tree Level Order Traversal |
Tree, BFS, Binary Tree, AMateList |
|
| 124 |
medium
|
721. Accounts Merge |
DFS, BFS, Union Find, Array, Backtracking, Hash Table, String, Sorting, AMateList |
|
| 125 |
medium
|
38. Count and Say |
String, AMateList |
|
| 126 |
easy
|
28. Find the Index of the First Occurrence in a String |
Array, Two Pointers, AMateList |
|
| 127 |
easy
|
26. Remove Duplicates from Sorted Array |
Array, Two Pointers, AMateList |
|
| 128 |
medium
|
698. Partition to K Equal Sum Subsets |
Bit Manipulation, Memonization, Array, DP, Backtracking, Bitmask, AMateList |
|
| 129 |
medium
|
2336. Smallest Number in Infinite Set |
Design, Hash Table, Heap(Priority Queue), AMateList |
|
| 130 |
medium
|
2300. Successful Pairs of Spells and Potions |
Array, Two Pointers, Binary Search, Sorting, AMateList |
|
| 131 |
medium
|
2352. Equal Row and Column Pairs |
Array, Hash Table, Matrix, Simulation, AMateList |
|
| 132 |
medium
|
2462. Total Cost to Hire K Workers |
Array, Two Pointers, Simulation, Heap |
|
| 133 |
easy
|
163. Missing Ranges |
Array, AMateList |
|
| 134 |
medium
|
162. Find Peak Element |
Array, Binary Search, Binary search |
|
| 135 |
medium
|
2542.Maximum Subsequence Score |
Greedy, Array, Sorting, Heap, AMateList |
|
| 136 |
medium
|
433. Minimum Genetic Mutation |
BFS, Hash Table, String, AMateList |
|
| 137 |
medium
|
649. Dota2 Senate |
Greedy, Queue, String, AMateList |
|
| 138 |
medium
|
547. Number of Provinces |
DFS, BFS, Union Find, Graph, AMateList |
|
| 139 |
medium
|
714. Best Time to Buy and Sell Stock with Transaction Fee |
Greedy, Array, DP, AMateList |
|
| 140 |
medium
|
841. Keys and Rooms |
DFS, BFS, Graph, AMateList |
|
| 141 |
medium
|
790. Domino and Tromino Tiling |
DP, AMateList |
|
| 142 |
medium
|
1041. Robot Bounded In Circle |
Math, String, Simulation, AMateList |
|
| 143 |
medium
|
909. Snakes and Ladders |
BFS, Array, Matrix |
|
| 144 |
medium
|
84. Largest Rectangle in Histogram |
Stack, Array, Monotonic Stack, AMateList |
|
| 145 |
medium
|
82. Remove Duplicates from Sorted List II |
Linkedlist, Twopointers, AMateList |
|
| 146 |
medium
|
8. String to Integer (atoi) |
String, AMateList |
|
| 147 |
medium
|
373. Find K Pairs with Smallest Sums |
Array, Heap |
|
| 148 |
medium
|
172. Factorial Trailing Zeroes |
Math |
|
| 149 |
medium
|
1657. Determine if Two Strings Are Close |
Hash Table, String, Counting, Sorting, AMateList |
|
| 150 |
medium
|
1466. Reorder Routes to Make All Paths Lead to the City Zero |
DFS, BFS, Graph, AMateList |
|
| 151 |
medium
|
1268. Search Suggestions System |
Tire, Array, String, Binary Search, Sorting, Heap, AMateList |
|
| 152 |
medium
|
92. Reverse Linked List II |
Linked List, Review, AMateList |
|
| 153 |
medium
|
76. Minimum Window Substring |
Hash Table, String, Sliding Window, Review, AMateList |
|
| 154 |
medium
|
694* |
Array, Prefix Sum, Sorting, Simulation, Heap, Review, AMateList |
|
| 155 |
medium
|
688* |
Array, Prefix Sum, Sorting, Simulation, Heap, Review, AMateList |
|
| 156 |
medium
|
687* |
Array, Prefix Sum, Sorting, Simulation, Heap, Review, AMateList |
|
| 157 |
medium
|
658* |
Array, Prefix Sum, Sorting, Simulation, Heap, Review, AMateList |
|
| 158 |
medium
|
622* |
Array, Prefix Sum, Sorting, Simulation, Heap, Review, AMateList |
|
| 159 |
medium
|
6* |
Array, Prefix Sum, Sorting, Simulation, Heap, Review, AMateList |
|
| 160 |
medium
|
536* |
Array, Prefix Sum, Sorting, Simulation, Heap, Review, AMateList |
|
| 161 |
medium
|
47. Permutations II |
Array, Backtracking, Review, AMateList |
|
| 162 |
medium
|
443. String Compression |
Two Pointers, String, Review, AMateList |
|
| 163 |
easy
|
408. Valid Word Abbreviation |
Two Pointers, String, AMateList |
|
| 164 |
medium
|
40* |
Array, Prefix Sum, Sorting, Simulation, Heap, AMateList |
|
| 165 |
hard
|
4* |
Array, Prefix Sum, Sorting, Simulation, Heap, Review, AMateList |
|
| 166 |
medium
|
393* |
Array, Prefix Sum, Sorting, Simulation, Heap, AMateList |
|
| 167 |
medium
|
388* |
Array, Prefix Sum, Sorting, Simulation, Heap, Review, AMateList |
|
| 168 |
medium
|
384* |
Array, Prefix Sum, Sorting, Simulation, Heap, Review, AMateList |
|
| 169 |
medium
|
378. Kth Smallest Element in a Sorted Matrix |
Array, Binary Search, Sorting, Heap, Matrix |
|
| 170 |
medium
|
34* |
Array, Prefix Sum, Sorting, Simulation, Heap, AMateList |
|
| 171 |
medium
|
300* |
Array, Prefix Sum, Sorting, Simulation, Heap, Review, AMateList |
|
| 172 |
medium
|
297* |
Array, Prefix Sum, Sorting, Simulation, Heap, Review, AMateList |
|
| 173 |
medium
|
295* |
Array, Prefix Sum, Sorting, Simulation, Heap, AMateList |
|
| 174 |
medium
|
247* |
Array, Prefix Sum, Sorting, Simulation, Heap, Review, AMateList |
|
| 175 |
medium
|
18* |
Array, Prefix Sum, Sorting, Simulation, Heap, Review, AMateList |
|
| 176 |
medium
|
16* |
Array, Prefix Sum, Sorting, Simulation, Heap, Review, AMateList |
|
| 177 |
medium
|
116* |
Array, Prefix Sum, Sorting, Simulation, Heap, AMateList |
|
| 178 |
medium
|
556. Next Greater Element III |
Math, Two Pointers, String, AMateList |
|
| 179 |
medium
|
1094. Car Pooling |
Array, Prefix Sum, Sorting, Simulation, Heap, AMateList |
|
| 180 |
medium
|
498. Diagonal Traverse |
Array, Matix, Simulation, Review, AMateList, Matrix |
|
| 181 |
medium
|
983. Minimum Cost For Tickets |
Array, DP, AMateList |
|
| 182 |
medium
|
735. Asteroid Collision |
Stack, Array, Simulation, Review, AMateList |
|
| 183 |
medium
|
713. Subarray Product Less Than K |
Array, Sliding Window, AMateList |
|
| 184 |
medium
|
5. Longest Palindromic Substring |
Two Pointers, String, DP, AMateList |
|
| 185 |
medium
|
437. Path Sum III |
Tree, Depth-First Search, Binary Tree, AMateList |
|
| 186 |
medium
|
678. Valid Parenthesis String |
Stack, Greedy, String, DP, AMateList |
|
| 187 |
medium
|
662. Maximum Width of Binary Tree |
Tree, Depth-First Search, Breadth-First Search, Binary Tree, AMateList |
|
| 188 |
hard
|
968. Binary Tree Cameras |
Tree, Depth-First Search, DP, Binary Tree, DFS |
|
| 189 |
medium
|
918. Maximum Sum Circular Subarray |
Queue, Array, Divide and Conquer, Dynamic Programming, Monotonic Queue, AMateList |
|
| 190 |
medium
|
865. Smallest Subtree with all the Deepest Nodes |
Tree, Depth-First Search, Breadth-First Search, Hash Table, Binary Tree, AMateList, DFS |
|
| 191 |
medium
|
525. Contiguous Array |
Array, Hash Table, Prefix Sum, AMateList |
|
| 192 |
medium
|
468. Validate IP Address |
String, AMateList |
|
| 193 |
hard
|
329* |
Tree, Depth-First Search, Breadth-First Search, Hash Table, Binary Tree, AMateList |
|
| 194 |
medium
|
1143. Longest Common Subsequence |
String, DP, AMateList |
|
| 195 |
medium
|
1008. Construct Binary Search Tree from Preorder Traversal |
Stack, Tree, Breadth-First Search, Array, Binary Tree, Monotonic Stack, AMateList |
|
| 196 |
hard
|
987. Vertical Order Traversal of a Binary Tree & 314 |
Tree, Depth-First Search, Breadth-First Search, Hash Table, Binary Tree, AMateList, DFS |
|
| 197 |
medium
|
647. Palindromic Substrings |
Two Pointers, String, DP, AMateList |
|
| 198 |
hard
|
540* |
Tree, Depth-First Search, Breadth-First Search, Hash Table, Binary Tree, AMateList |
|
| 199 |
hard
|
435* |
Tree, Depth-First Search, Breadth-First Search, Hash Table, Binary Tree, AMateList |
|
| 200 |
hard
|
430* |
Tree, Depth-First Search, Breadth-First Search, Hash Table, Binary Tree, AMateList |
|
| 201 |
medium
|
314. Binary Tree Vertical Order Traversal & 987 |
Tree, Depth-First Search, Breadth-First Search, Hash Table, Binary Tree, AMateList, DFS |
|
| 202 |
hard
|
1209* |
Tree, Depth-First Search, Breadth-First Search, Hash Table, Binary Tree, AMateList |
|
| 203 |
hard
|
23. Merge k Sorted Lists |
Linked List, Divide and Conquer, Heap, Merge Sort, Review, AMateList |
|
| 204 |
medium
|
621. Task Scheduler |
Greedy, Array, Hash Table, Counting, Sorting, Heap, Review |
|
| 205 |
medium
|
416. Partition Equal Subset Sum |
Array, DP, Review, AMateList |
|
| 206 |
medium
|
981. Time Based Key-Value Store |
Design, Hash Table, String, Binary Search |
|
| 207 |
easy
|
543. Diameter of Binary Tree |
Tree, DFS, Binary Tree, Review |
|
| 208 |
medium
|
236. Lowest Common Ancestor of a Binary Tree |
Tree, DFS, Binary Tree, Review |
|
| 209 |
medium
|
235. Lowest Common Ancestor of a Binary Search Tree |
Tree, DFS, Binary Tree, BST, Review, AMateList |
|
| 210 |
medium
|
542. 01 Matrix |
BFS, Array, DP, Matrix, Review |
|
| 211 |
medium
|
15. 3Sum |
Array, Two Pointers, Sorting, Review |
|
| 212 |
medium
|
845. Longest Mountain in Array |
Array, Two Pointers, DP, Enumeration, Review |
|
| 213 |
easy
|
706. Design HashMap |
Design, Array, Hash Table, Linked List, Hash Function, Memory |
|
| 214 |
hard
|
719. Find K-th Smallest Pair Distance |
Array, Two Pointers, Binary Search, Sorting, Review |
|
| 215 |
hard
|
995. Minimum Number of K Consecutive Bit Flips |
Bit Manipulation, Queue, Array, Prefix Sum, Sliding Window, Review |
|
| 216 |
medium
|
978. Longest Turbulent Subarray |
Array, DP, Sliding Window, Review |
|
| 217 |
medium
|
438. Find All Anagrams in a String |
Hash Table, String, Sliding Window, Review, AMateList |
|
| 218 |
medium
|
1695. Maximum Erasure Value |
Hash Table, Array, Sliding Window, Review |
|
| 219 |
medium
|
3. Longest Substring Without Repeating Characters |
Hash Table, String, Sliding Window, Review |
|
| 220 |
medium
|
209. Minimum Size Subarray Sum |
Array, Binary Search, Prefix Sum, Sliding Window, Review, AMateList |
|
| 221 |
medium
|
424. Longest Repeating Character Replacement |
Hash Table, String, Sliding Window, Review, AMateList |
|
| 222 |
medium
|
1658. Minimum Operations to Reduce X to Zero |
Array, Hash Table, Binary Search, Prefix Sum, Sliding Window, Review |
|
| 223 |
easy
|
1071. Greatest Common Divisor of Strings |
Math, String |
|
| 224 |
easy
|
278. First Bad Version |
Binary Search, Interactive |
|
| 225 |
medium
|
275. H-Index II |
Array, Binary Search |
|
| 226 |
medium
|
274. H-Index |
Array, Counting Sort, Sorting |
|
| 227 |
medium
|
93. Restore IP Addresses |
String, Backtracking, Review |
|
| 228 |
hard
|
332. Reconstruct Itinerary |
Depth-First Search, Graph, Eulerian Circuit, Review, AMateList, DFS |
|
| 229 |
easy
|
326. Power of Three |
Recursion, Math |
|
| 230 |
Medium
|
310. Minimum Height Trees |
DFS, BFS, Graph, Topological Sort, Review, AMateList |
|
| 231 |
medium
|
279. Perfect Squares |
BFS, Math, DP, Review |
|
| 232 |
easy
|
270 Closest Binary Search Tree Value |
Tree, Depth-First Search, Binary Search Tree, Binary Search, Binary Tree, Review |
|
| 233 |
medium
|
268 Missing Number |
Bit Manipulation, Array, Hash Table, Math, Binary Search, Sorting |
|
| 234 |
easy
|
412. Fizz Buzz |
Math, String, Simulation |
|
| 235 |
easy
|
409. Longest Palindrome |
Greedy, Hash Table, String |
|
| 236 |
medium
|
406. Queue Reconstruction by Height |
Greedy, Binary Indexed Tree, Segment Tree, Array, Sorting, Review |
|
| 237 |
easy
|
404. Sum of Left Leaves |
Math, Binary Search, Review |
|
| 238 |
medium
|
402. Remove K Digits |
Stack, Greedy, String, Monotonic Stack |
|
| 239 |
medium
|
399. Evaluate Division |
DFS, BFS, Union Find, Graph, Array, Shortest Path, Review |
|
| 240 |
medium
|
395. Longest Substring with At Least K Repeating Characters |
Hash Table, String, Divide and Conquer, Sliding Window, Review, Memory |
|
| 241 |
easy
|
392. Is Subsequence |
Two Pointers, String, DP |
|
| 242 |
easy
|
389. Find the Difference |
Bit Manipulation, Hash Table, String, Sorting |
|
| 243 |
easy
|
387. First Unique Character in a String |
Queue, Hash Table, String, Counting |
|
| 244 |
easy
|
383. Ransom Note |
Hash Table, String, Counting |
|
| 245 |
medium
|
367. Valid Perfect Square |
Reservioir Sampling, Linked List, Math, Randomized |
|
| 246 |
medium
|
380. Insert Delete GetRandom O(1) |
Design, Array, Hash Table, Math, Randomized, Review |
|
| 247 |
medium
|
377. Combination Sum IV |
Array, DP, Review |
|
| 248 |
medium
|
376. Wiggle Subsequence |
Greedy, Array, DP |
|
| 249 |
medium
|
368. Largest Divisible Subset |
Array, Math, DP, Sorting, AMateList |
|
| 250 |
easy
|
367. Valid Perfect Square |
Math, Binary Search |
|
| 251 |
easy
|
359. Logger Rate Limiter |
Design, Hash Table |
|
| 252 |
easy
|
350. Intersection of Two Arrays II |
Array, Hash Table, Two Pointers, Binary Search, Sorting |
|
| 253 |
easy
|
347. Top K Frequent Elements |
Array, Hash Table, Divide and Conquer, Bucket Sort, Counting, Quickselect, Sorting, Heap |
|
| 254 |
easy
|
346. Moving Average from Data Stream |
Design, Queue, Array, Data Stream |
|
| 255 |
easy
|
344. Reverse String |
Two Pointers, String |
|
| 256 |
easy
|
342. Power of Four |
Bit Manipulation, Recursion, Math |
|
| 257 |
easy
|
338. Counting Bits |
Bit Manipulation, DP, Review, AMateList |
|
| 258 |
easy
|
337. House Robber III |
Tree, Depth-First Search, DP, Binary Tree, Review, DFS/DP |
|
| 259 |
medium
|
334. Increasing Triplet Subsequence |
Greedy, Array, Review |
|
| 260 |
hard
|
329. Longest Increasing Path in a Matrix |
Depth-First Search, Breadth-First Search, Graph, Topological Sort, Memoization, Array, Dynamic Programming, Matrix, Review |
|
| 261 |
medium
|
328. Odd Even Linked List |
Linked List |
|
| 262 |
easy
|
322. Coin Change |
Breadth-First Search, Array, Dynamic Programming |
|
| 263 |
medium
|
319. Bulb Switcher |
Brainteaser, Math, Review |
|
| 264 |
medium
|
316. Remove Duplicate Letters |
Stack, Greedy, String, Monotonic Stack, Review |
|
| 265 |
easy
|
304. Range Sum Query 2D - Immutable |
Design, Array, Matrix, Prefix Sum, Review |
|
| 266 |
easy
|
303. Range Sum Query - Immutable |
Design, Array, Prefix SUm |
|
| 267 |
medium
|
299. Bulls and Cows |
Hash Table, String, Counting, Two Pointers |
|
| 268 |
easy
|
290. Word Pattern |
Hash Table, String |
|
| 269 |
easy
|
289. Game of Life |
Array, Matrix, Simulation, AMateList |
|
| 270 |
medium
|
287. Find the Duplicate Number |
Array, Two Pointers, Binary Search, AMateList |
|
| 271 |
medium
|
284. Peeking Iterator |
Design, Array, Iterator |
|
| 272 |
easy
|
283. Move Zeroes |
Array, Two Pointers |
|
| 273 |
medium
|
264. Ugly Number II |
Hash Table, Math, Dynamic Programming, Heap(Priority Queue), Review, Heap |
|
| 274 |
medium
|
260. Single Number III |
Bit Manipulation, Array, Review, AMateList |
|
| 275 |
easy
|
258. Add Digits |
Math, Number Theory, Simulation |
|
| 276 |
medium
|
1306. Jump Game III |
DFS, BFS, Array |
|
| 277 |
medium
|
237. Delete Node in a Linked List |
Linked List |
|
| 278 |
medium
|
238. Product of Array Except Self |
Array, Prefix Sum, AMateList, Prefix/Suffix |
|
| 279 |
medium
|
230. Kth Smallest Element in a BST |
Tree, DFS, BST |
|
| 280 |
medium
|
242. Valid Anagram |
Hash Table, String, Sorting |
|
| 281 |
medium
|
239. Sliding Window Maximum |
Array, Prefix Sum, Review, AMateList |
|
| 282 |
medium
|
229. Majority Element II |
Array, Hash Table, Counting, Sorting, Review, AMateList |
|
| 283 |
easy
|
228. Summary Ranges |
Array |
|
| 284 |
medium
|
227. Basic Calculator II |
Stack, Math, String |
|
| 285 |
medium
|
226. Invert Binary Tree |
Tree, DFS, Binary Search, Binary Tree |
|
| 286 |
medium
|
222. Count Complete Tree Nodes |
Tree, DFS, Binary Search, Binary Tree, Review |
|
| 287 |
medium
|
221. Maximal Square |
Hash Table, String, DP |
|
| 288 |
hard
|
220. Contains Duplicate III |
Array, Bucket Sort, Ordered Set, Sorting, Sliding Window, Review |
|
| 289 |
medium
|
216. Combination Sum III |
Array, Backtracking, Review |
|
| 290 |
medium
|
213. House Robber II |
Array, Dynamic Programming, Review |
|
| 291 |
medium
|
212. Word Search II |
Trie, Array, String, Backtracking, Matrix, Review, AMateList |
|
| 292 |
medium
|
211. Design Add and Search Words Data Structure |
DFS, Design, Trie, String, Review |
|
| 293 |
medium
|
210. Course Schedule II |
DFS, BFS, Graph, Topological Sort, Review, AMateList |
|
| 294 |
medium
|
309. Best Time to Buy and Sell Stock with Cooldown |
Array, DP, Review, AMateList |
|
| 295 |
medium
|
208. Implement Trie (Prefix Tree) |
Design, Trie, Hash Table, String |
|
| 296 |
medium
|
207. Course Schedule |
DFS, BFS, Graph, Topological Sort, Review, AMateList, BFS/DFS |
|
| 297 |
medium
|
205. Isomorphic Strings |
Hash Table, String |
|
| 298 |
easy
|
206. Reverse Linked List |
Recursion, Linked List |
|
| 299 |
medium
|
202. Happy Number |
Hash Table, Math, Two Pointers, AMateList |
|
| 300 |
easy
|
231. Power of Two |
Bit Manipulation, Recursion, Math |
|
| 301 |
hard
|
174. Dungeon Game |
Array, Dynamic Programming, Matrix, Review |
|
| 302 |
medium
|
201. Bitwise AND of Numbers Range |
Bit Manipulation |
|
| 303 |
medium
|
200. Number of Islands |
DFS, BFS, Union Find, Array, Matrix, Review |
|
| 304 |
medium
|
198. House Robber |
Array, Dynamic Programming |
|
| 305 |
medium
|
188. Best Time to Buy and Sell Stock IV* |
Array, DP |
|
| 306 |
medium
|
187. Repeated DNA Sequences |
Bit Maniputation, Hash Table, String, Sliding Window, Hash Function, Rolling Hash |
|
| 307 |
medium
|
203. Remove Linked List Elements |
Tree, DFS, BFS, Binary Tree, Review |
|
| 308 |
medium
|
173. Binary Search Tree Iterator |
Stack, Tree, Design, Binary Search Tree, Binary Tree, Iterator, Review, AMateList |
|
| 309 |
easy
|
171. Excel Sheet Column Number |
Math, String |
|
| 310 |
easy
|
169. Majority Element |
Array, Hash Table, Divide and Conquer, Counting, Sorting |
|
| 311 |
medium
|
165. Compare Version Numbers |
Two Pointers, String |
|
| 312 |
easy
|
160. Intersection of Two Linked Lists |
Hash Table, Linked List, Two Pointers |
|
| 313 |
medium
|
155. Min Stack |
Stack, Design |
|
| 314 |
hard
|
154. Find Minimum in Rotated Sorted Array II |
Array, Binary Search |
|
| 315 |
medium
|
152. Maximum Product Subarray |
Array, DP, Review |
|
| 316 |
medium
|
199. Binary Tree Right Side View |
Tree, DFS, BFS, Binary Tree, Review |
|
| 317 |
medium
|
151. Reverse Words in a String |
Two pointers, String, Two Pointers |
|
| 318 |
hard
|
127. Word Ladder |
BFS, Hash Table, String, Review, AMateList |
|
| 319 |
hard
|
126. Word Ladder II |
BFS, Hash Table, String, Backtracking, Review, AMateList |
|
| 320 |
easy
|
190. Reverse Bits |
Bit Manipulation, Divide and Conquer |
|
| 321 |
medium
|
179. Largest Number |
Greedy, Array, String, Sortin, Review |
|
| 322 |
easy
|
191. Number of 1 Bits |
Bit Manipultation, Divide and Conquer |
|
| 323 |
medium
|
189. Rotate Array |
Array, Math, Two Pointers |
|
| 324 |
medium
|
147. Insertion Sort List |
Linked List, Sorting |
|
| 325 |
easy
|
145. Binary Tree Postorder Traversal |
Stack, Tree, DFS, Binary Tree, Review |
|
| 326 |
easy
|
144. Binary Tree Preorder Traversal |
Stack, Tree, DFS, Binary Tree |
|
| 327 |
medium
|
143. Reorder List |
Stack, Recursion, Linked List, Two Pointers |
|
| 328 |
medium
|
142. Linked List Cycle II |
Hash Table, Linked List, Two Pointers |
|
| 329 |
easy
|
141. Linked List Cycle |
Hash Table, Linked List, Two Pointers |
|
| 330 |
medium
|
140. Word Break II |
Trie, Memoization, Array, Hash Table, String, Dynamic Programming, Backtracking, Review, AMateList |
|
| 331 |
medium
|
139. Word Break |
Trie, Memoization, Array, Hash Table, String, Dynamic Programming |
|
| 332 |
medium
|
138. Copy List with Random Pointer |
Hash Table, Linked List, Review |
|
| 333 |
medium
|
148. Sort List |
Linked List, Two Pointers, Divide and Conquer, Sorting, Merge Sort, Review |
|
| 334 |
easy
|
136. Single Number |
Bit Manipulation, Array |
|
| 335 |
medium
|
134. Gas Station |
Greedy, Array |
|
| 336 |
medium
|
133. Clone Graph |
DFS, BFS, Graph, Hash Table, Review |
|
| 337 |
medium
|
137. Single Number II |
Bit Maniputation, Array |
|
| 338 |
medium
|
130. Surrounded Regions |
DFS, BFS, Union Find, Array, Matrix, Review |
|
| 339 |
hard
|
124. Binary Tree Maximum Path Sum |
Tree, DFS, DP, Binary Tree, Review, AMateList |
|
| 340 |
easy
|
125. Valid Palindrome |
Two points, String, Two Pointers |
|
| 341 |
hard
|
123. Best Time to Buy and Sell Stock III |
Array, DP, Review |
|
| 342 |
medium
|
122. Best Time to Buy and Sell Stock II |
Greedy, Array, DP |
|
| 343 |
easy
|
121. Best Time to Buy and Sell Stock |
Array, DP |
|
| 344 |
medium
|
120. Triangle |
Array, DP |
|
| 345 |
easy
|
119. Pascal's Triangle II |
Array, DP, Review |
|
| 346 |
medium
|
117. Populating Next Right Pointers in Each Node II |
Tree, Array, Hash Table, Divide and Conquer, Binary Tree, Review |
|
| 347 |
medium
|
129. Sum Root to Leaf Numbers |
Tree, Array, Hash Table, Divide and Conquer, Binary Tree, DFS |
|
| 348 |
hard
|
132. Palindrome Partitioning II |
String, DP, Review |
|
| 349 |
medium
|
113. Path Sum II |
Tree, DFS, Backtracking, Binary Tree, Review, AMateList |
|
| 350 |
easy
|
111. Minimum Depth of Binary Tree |
Tree, DFS, BFS, Binary Tree, Review, AMateList |
|
| 351 |
easy
|
110. Balanced Binary Tree |
Tree, DFS, Binary Tree, Review, AMateList |
|
| 352 |
easy
|
104. Maximum Depth of Binary Tree |
Tree, DFS, BFS, Binary Tree, Review |
|
| 353 |
medium
|
103. Binary Tree Zigzag Level Order Traversal |
Tree, BFS, Binary Tree, AMateList |
|
| 354 |
easy
|
98. Validate Binary Search Tree |
Memoization, Math, DP, Review |
|
| 355 |
medium
|
96. Unique Binary Search Trees |
Tree, BST, Math, DP, Binary Tree |
|
| 356 |
medium
|
91. Decode Ways |
String, DP, Review |
|
| 357 |
hard
|
87. Scramble String |
String, DP, Review |
|
| 358 |
easy
|
94. Binary Tree Inorder Traversal |
Stack, Tree, DFS, Binary Tree |
|
| 359 |
medium
|
80. Remove Duplicates from Sorted Array II |
Array, Two Pointers, Review, AMateList |
|
| 360 |
medium
|
79. Word Search |
Array, Backtracking, Matrix, AMateList |
|
| 361 |
medium
|
90. Subsets II |
Array, Backtracking |
|
| 362 |
medium
|
106. Construct Binary Tree from Inorder and Postorder Traversal |
Tree, Array, Hash Table, Divide and Conquer, Binary Tree, Review |
|
| 363 |
medium
|
95. Unique Binary Search Trees II |
Tree, BST, DP, Backtracking, Binary Tree, Review |
|
| 364 |
medium
|
78. Subsets |
Array, Backtracking |
|
| 365 |
medium
|
75. Sort Colors |
Array, Two Pointers, Sorting, Review |
|
| 366 |
medium
|
74. Search a 2D Matrix |
Array, Binary Search, Matrix, AMateList |
|
| 367 |
medium
|
73. Set Matrix Zeroes |
Array, Hash Table, Matrix |
|
| 368 |
hard
|
72. Edit Distance |
String, DP, AMateList |
|
| 369 |
medium
|
71. Simplify Path |
Stack, String, Review |
|
| 370 |
easy
|
70. Climbing Stairs |
Memoization, Math, DP |
|
| 371 |
medium
|
59. Spiral Matrix II |
Array, Matrix, Simulation |
|
| 372 |
medium
|
107. Binary Tree Level Order Traversal II |
Tree, BFS, Binary Tree |
|
| 373 |
easy
|
100. Same Tree |
Tree, DFS, BFS, Binary Tree |
|
| 374 |
medium
|
64. Minimum Path Sum |
Array, DP, Matrix |
|
| 375 |
medium
|
63. Unique Paths II |
Array, DP, Matrix |
|
| 376 |
hard
|
61. Rotate List |
Linked list, Two Pointers |
|
| 377 |
easy
|
67. Add Binary |
Math, String, Simulation, Bit Manipulation |
|
| 378 |
Hard
|
60. Permutation Sequence |
Array, Review |
|
| 379 |
easy
|
66. Plus One |
Array, Math |
|
| 380 |
medium
|
62. Unique Paths |
Math, DP, Combinatorics |
|
| 381 |
medium
|
57. Insert Interval |
Array, Matrix, Simulation |
|
| 382 |
easy
|
58. Length of Last Word |
String |
|
| 383 |
medium
|
56. Merge Intervals |
Array, Sorting |
|
| 384 |
medium
|
55. Jump Game |
Greedy, Array, DP |
|
| 385 |
easy
|
53. Maximum Subarray |
Array, Divide and Conquer, DP, AMateList |
|
| 386 |
medium
|
50. Pow(x, n) |
Recursion, Math |
|
| 387 |
medium
|
49. Group Anagrams |
Array, Hash Table, String, Sorting |
|
| 388 |
medium
|
48. Rotate Image |
Array, Math, Matrix |
|
| 389 |
hard
|
45. Jump Game II |
Array, Greedy, DP, AMateList |
|
| 390 |
hard
|
41. First Missing Positive |
Array, BT, Review, AMateList |
|
| 391 |
medium
|
39. Combination Sum |
Array, BT |
|
| 392 |
medium
|
36. Valid Sudoku |
Array, Hash Table, Matrix |
|
| 393 |
easy
|
35. Search Insert Position |
Stack, String, DP |
|
| 394 |
hard
|
32. Longest Valid Parentheses |
Stack, String, DP |
|
| 395 |
medium
|
33. Search in Rotated Sorted Array |
Array, Binary Search |
|
| 396 |
medium
|
31. Next Permutation |
Array, Two Points, AMateList |
|
| 397 |
medium
|
24. Swap Nodes in Pairs |
Linked List, Recursion |
|
| 398 |
medium
|
54. Spiral Matrix |
Array, Matrix, Simulation, AMateList |
|
| 399 |
medium
|
450. Delete Node in a BST |
Tree, BST, BT, Review |
|
| 400 |
hard
|
312. Burst Balloons* |
Array, DP |
|
