Leetcode Easy Solutions
id Leetcode 394 Easy Solutions Level
1 Two Sum Easy
9 Palindrome Number Easy
13 Roman to Integer Easy
14 Longest Common Prefix Easy
20 Valid Parentheses Easy
21 Merge Two Sorted Lists Easy
26 Remove Duplicates from Sorted Array Easy
27 Remove Element Easy
28 Implement strStr() Easy
35 Search Insert Position Easy
53 Maximum Subarray Easy
58 Length of Last Word Easy
66 Plus One Easy
67 Add Binary Easy
69 Sqrt(x) Easy
70 Climbing Stairs Easy
83 Remove Duplicates from Sorted List Easy
88 Merge Sorted Array Easy
94 Binary Tree Inorder Traversal Easy
100 Same Tree Easy
101 Symmetric Tree Easy
104 Maximum Depth of Binary Tree Easy
108 Convert Sorted Array to Binary Search Tree Easy
110 Balanced Binary Tree Easy
111 Minimum Depth of Binary Tree Easy
112 Path Sum Easy
118 Pascal's Triangle Easy
121 Best Time to Buy and Sell Stock Easy
125 Valid Palindrome Easy
136 Single Number Easy
144 Binary Tree Preorder Traversal Easy
145 Binary Tree Postorder Traversal Easy
155 Min Stack Easy
157 Read N Characters Given Read4 Easy
163 Missing Ranges Easy
167 Two Sum II - Input Array Is Sorted Easy
168 Excel Sheet Column Title Easy
169 Majority Element Easy
170 Two Sum III - Data structure design Easy
171 Excel Sheet Column Number Easy
190 Reverse Bits Easy
191 Number of 1 Bits Easy
202 Happy Number Easy
203 Remove Linked List Elements Easy
205 Isomorphic Strings Easy
206 Reverse Linked List Easy
217 Contains Duplicate Easy
219 Contains Duplicate II Easy
225 Implement Stack using Queues Easy
226 Invert Binary Tree Easy
228 Summary Ranges Easy
231 Power of Two Easy
232 Implement Queue using Stacks Easy
234 Palindrome Linked List Easy
235 Lowest Common Ancestor of a Binary Search Tree Easy
242 Valid Anagram Easy
243 Shortest Word Distance Easy
246 Strobogrammatic Number Easy
252 Meeting Rooms Easy
257 Binary Tree Paths Easy
258 Add Digits Easy
263 Ugly Number Easy
266 Palindrome Permutation Easy
268 Missing Number Easy
270 Closest Binary Search Tree Value Easy
278 First Bad Version Easy
283 Move Zeroes Easy
290 Word Pattern Easy
292 Nim Game Easy
293 Flip Game Easy
303 Range Sum Query - Immutable Easy
326 Power of Three Easy
338 Counting Bits Easy
342 Power of Four Easy
344 Reverse String Easy
345 Reverse Vowels of a String Easy
346 Moving Average from Data Stream Easy
349 Intersection of Two Arrays Easy
350 Intersection of Two Arrays II Easy
359 Logger Rate Limiter Easy
367 Valid Perfect Square Easy
374 Guess Number Higher or Lower Easy
383 Ransom Note Easy
387 First Unique Character in a String Easy
389 Find the Difference Easy
392 Is Subsequence Easy
401 Binary Watch Easy
404 Sum of Left Leaves Easy
405 Convert a Number to Hexadecimal Easy
408 Valid Word Abbreviation Easy
409 Longest Palindrome Easy
412 Fizz Buzz Easy
414 Third Maximum Number Easy
415 Add Strings Easy
422 Valid Word Square Easy
434 Number of Segments in a String Easy
441 Arranging Coins Easy
448 Find All Numbers Disappeared in an Array Easy
455 Assign Cookies Easy
459 Repeated Substring Pattern Easy
461 Hamming Distance Easy
463 Island Perimeter Easy
476 Number Complement Easy
482 License Key Formatting Easy
485 Max Consecutive Ones Easy
492 Construct the Rectangle Easy
495 Teemo Attacking Easy
496 Next Greater Element I Easy
500 Keyboard Row Easy
501 Find Mode in Binary Search Tree Easy
504 Base 7 Easy
506 Relative Ranks Easy
507 Perfect Number Easy
509 Fibonacci Number Easy
520 Detect Capital Easy
521 Longest Uncommon Subsequence I Easy
530 Minimum Absolute Difference in BST Easy
541 Reverse String II Easy
543 Diameter of Binary Tree Easy
551 Student Attendance Record I Easy
557 Reverse Words in a String III Easy
561 Array Partition I Easy
563 Binary Tree Tilt Easy
566 Reshape the Matrix Easy
572 Subtree of Another Tree Easy
575 Distribute Candies Easy
594 Longest Harmonious Subsequence Easy
598 Range Addition II Easy
599 Minimum Index Sum of Two Lists Easy
604 Design Compressed String Iterator Easy
605 Can Place Flowers Easy
606 Construct String from Binary Tree Easy
617 Merge Two Binary Trees Easy
628 Maximum Product of Three Numbers Easy
637 Average of Levels in Binary Tree Easy
643 Maximum Average Subarray I Easy
645 Set Mismatch Easy
653 Two Sum IV - Input is a BST Easy
657 Robot Return to Origin Easy
661 Image Smoother Easy
671 Second Minimum Node In a Binary Tree Easy
674 Longest Continuous Increasing Subsequence Easy
680 Valid Palindrome II Easy
682 Baseball Game Easy
693 Binary Number with Alternating Bits Easy
696 Count Binary Substrings Easy
697 Degree of an Array Easy
700 Search in a Binary Search Tree Easy
703 Kth Largest Element in a Stream Easy
704 Binary Search Easy
705 Design HashSet Easy
706 Design HashMap Easy
709 To Lower Case Easy
716 Max Stack Easy
717 1-bit and 2-bit Characters Easy
724 Find Pivot Index Easy
728 Self Dividing Numbers Easy
733 Flood Fill Easy
734 Sentence Similarity Easy
744 Find Smallest Letter Greater Than Target Easy
746 Min Cost Climbing Stairs Easy
747 Largest Number At Least Twice of Others Easy
748 Shortest Completing Word Easy
760 Find Anagram Mappings Easy
762 Prime Number of Set Bits in Binary Representation Easy
766 Toeplitz Matrix Easy
771 Jewels and Stones Easy
783 Minimum Distance Between BST Nodes Easy
796 Rotate String Easy
800 Similar RGB Color Easy
804 Unique Morse Code Words Easy
806 Number of Lines To Write String Easy
812 Largest Triangle Area Easy
819 Most Common Word Easy
821 Shortest Distance to a Character Easy
824 Goat Latin Easy
830 Positions of Large Groups Easy
832 Flipping an Image Easy
836 Rectangle Overlap Easy
844 Backspace String Compare Easy
852 Peak Index in a Mountain Array Easy
859 Buddy Strings Easy
860 Lemonade Change Easy
867 Transpose Matrix Easy
868 Binary Gap Easy
872 Leaf-Similar Trees Easy
876 Middle of the Linked List Easy
883 Projection Area of 3D Shapes Easy
884 Uncommon Words from Two Sentences Easy
888 Fair Candy Swap Easy
892 Surface Area of 3D Shapes Easy
896 Monotonic Array Easy
897 Increasing Order Search Tree Easy
905 Sort Array By Parity Easy
908 Smallest Range I Easy
914 X of a Kind in a Deck of Cards Easy
917 Reverse Only Letters Easy
922 Sort Array By Parity II Easy
925 Long Pressed Name Easy
929 Unique Email Addresses Easy
933 Number of Recent Calls Easy
937 Reorder Data in Log Files Easy
938 Range Sum of BST Easy
941 Valid Mountain Array Easy
942 DI String Match Easy
944 Delete Columns to Make Sorted Easy
953 Verifying an Alien Dictionary Easy
961 N-Repeated Element in Size 2N Array Easy
965 Univalued Binary Tree Easy
976 Largest Perimeter Triangle Easy
977 Squares of a Sorted Array Easy
989 Add to Array-Form of Integer Easy
993 Cousins in Binary Tree Easy
997 Find the Town Judge Easy
999 Available Captures for Rook Easy
1002 Find Common Characters Easy
1005 Maximize Sum Of Array After K Negations Easy
1009 Complement of Base 10 Integer Easy
1013 Partition Array Into Three Parts With Equal Sum Easy
1018 Binary Prefix Divisible By 5 Easy
1021 Remove Outermost Parentheses Easy
1022 Sum of Root To Leaf Binary Numbers Easy
1025 Divisor Game Easy
1030 Matrix Cells in Distance Order Easy
1037 Valid Boomerang Easy
1046 Last Stone Weight Easy
1047 Remove All Adjacent Duplicates In String Easy
1051 Height Checker Easy
1056 Confusing Number Easy
1064 Fixed Point Easy
1065 Index Pairs of a String Easy
1071 Greatest Common Divisor of Strings Easy
1078 Occurrences After Bigram Easy
1085 Sum of Digits in the Minimum Number Easy
1086 High Five Easy
1089 Duplicate Zeros Easy
1099 Two Sum Less Than K Easy
1103 Distribute Candies to People Easy
1108 Defanging an IP Address Easy
1114 Print in Order Easy
1118 Number of Days in a Month Easy
1119 Remove Vowels from a String Easy
1122 Relative Sort Array Easy
1128 Number of Equivalent Domino Pairs Easy
1133 Largest Unique Number Easy
1134 Armstrong Number Easy
1137 N-th Tribonacci Number Easy
1150 Check If a Number Is Majority Element in a Sorted Array Easy
1154 Day of the Year Easy
1160 Find Words That Can Be Formed by Characters Easy
1165 Single-Row Keyboard Easy
1175 Prime Arrangements Easy
1176 Diet Plan Performance Easy
1180 Count Substrings with Only One Distinct Letter Easy
1184 Distance Between Bus Stops Easy
1185 Day of the Week Easy
1189 Maximum Number of Balloons Easy
1196 How Many Apples Can You Put into the Basket Easy
1200 Minimum Absolute Difference Easy
1207 Unique Number of Occurrences Easy
1213 Intersection of Three Sorted Arrays Easy
1217 Minimum Cost to Move Chips to The Same Position Easy
1221 Split a String in Balanced Strings Easy
1228 Missing Number In Arithmetic Progression Easy
1232 Check If It Is a Straight Line Easy
1243 Array Transformation Easy
1252 Cells with Odd Values in a Matrix Easy
1260 Shift 2D Grid Easy
1266 Minimum Time Visiting All Points Easy
1271 Hexspeak Easy
1275 Find Winner on a Tic Tac Toe Game Easy
1279 Traffic Light Controlled Intersection Easy
1281 Subtract the Product and Sum of Digits of an Integer Easy
1287 Element Appearing More Than 25% In Sorted Array Easy
1290 Convert Binary Number in a Linked List to Integer Easy
1295 Find Numbers with Even Number of Digits Easy
1299 Replace Elements with Greatest Element on Right Side Easy
1304 Find N Unique Integers Sum up to Zero Easy
1309 Decrypt String from Alphabet to Integer Mapping Easy
1313 Decompress Run-Length Encoded List Easy
1317 Convert Integer to the Sum of Two No-Zero Integers Easy
1323 Maximum 69 Number Easy
1331 Rank Transform of an Array Easy
1332 Remove Palindromic Subsequences Easy
1337 The K Weakest Rows in a Matrix Easy
1342 Number of Steps to Reduce a Number to Zero Easy
1346 Check If N and Its Double Exist Easy
1351 Count Negative Numbers in a Sorted Matrix Easy
1356 Sort Integers by The Number of 1 Bits Easy
1360 Number of Days Between Two Dates Easy
1365 How Many Numbers Are Smaller Than the Current Number Easy
1370 Increasing Decreasing String Easy
1374 Generate a String With Characters That Have Odd Counts Easy
1380 Lucky Numbers in a Matrix Easy
1385 Find the Distance Value Between Two Arrays Easy
1389 Create Target Array in the Given Order Easy
1394 Find Lucky Integer in an Array Easy
1399 Count Largest Group Easy
1636 Sort Array by Increasing Frequency Easy
1640 Check Array Formation Through Concatenation Easy
1646 Get Maximum in Generated Array Easy
1652 Defuse the Bomb Easy
1656 Design an Ordered Stream Easy
1668 Maximum Repeating Substring Easy
1678 Goal Parser Interpretation Easy
1684 Count the Number of Consistent Strings Easy
1688 Count of Matches in Tournament Easy
1694 Reformat Phone Number Easy
1700 Number of Students Unable to Eat Lunch Easy
1704 Determine if String Halves Are Alike Easy
1708 Largest Subarray Length K Easy
1710 Maximum Units on a Truck Easy
1716 Calculate Money in Leetcode Bank Easy
1720 Decode XORed Array Easy
1725 Number Of Rectangles That Can Form The Largest Square Easy
1732 Find the Highest Altitude Easy
1736 Latest Time by Replacing Hidden Digits Easy
1748 Sum of Unique Elements Easy
1752 Check if Array Is Sorted and Rotated Easy
1758 Minimum Changes To Make Alternating Binary String Easy
1773 Count Items Matching a Rule Easy
1779 Find Nearest Point That Has the Same X or Y Coordinate Easy
1784 Check if Binary String Has at Most One Segment of Ones Easy
1790 Check if One String Swap Can Make Strings Equal Easy
1791 Find Center of Star Graph Easy
1796 Second Largest Digit in a String Easy
1800 Maximum Ascending Subarray Sum Easy
1805 Number of Different Integers in a String Easy
1812 Determine Color of a Chessboard Square Easy
1816 Truncate Sentence Easy
1822 Sign of the Product of an Array Easy
1826 Faulty Sensor Easy
1827 Minimum Operations to Make the Array Increasing Easy
1832 Check if the Sentence Is Pangram Easy
1837 Sum of Digits in Base K Easy
1844 Replace All Digits with Characters Easy
1848 Minimum Distance to the Target Element Easy
1854 Maximum Population Year Easy
1859 Sorting the Sentence Easy
1863 Sum of All Subset XOR Totals Easy
1869 Longer Contiguous Segments of Ones than Zeros Easy
1876 Substrings of Size Three with Distinct Characters Easy
1880 Check if Word Equals Summation of Two Words Easy
1886 Determine Whether Matrix Can Be Obtained By Rotation Easy
1893 Check if All the Integers in a Range Are Covered Easy
1897 Redistribute Characters to Make All Strings Equal Easy
1903 Largest Odd Number in String Easy
1909 Remove One Element to Make the Array Strictly Increasing Easy
1913 Maximum Product Difference Between Two Pairs Easy
1920 Build Array from Permutation Easy
1925 Count Square Sum Triples Easy
1929 Concatenation of Array Easy
1933 Check if String Is Decomposable Into Value-Equal Substrings Easy
1935 Maximum Number of Words You Can Type Easy
1941 Check if All Characters Have Equal Number of Occurrences Easy
1945 Sum of Digits of String After Convert Easy
1952 Three Divisors Easy
1957 Delete Characters to Make Fancy String Easy
1961 Check If String Is a Prefix of Array Easy
1967 Number of Strings That Appear as Substrings in Word Easy
1971 Find if Path Exists in Graph Easy
1974 Minimum Time to Type Word Using Special Typewriter Easy
1979 Find Greatest Common Divisor of Array Easy
1984 Minimum Difference Between Highest and Lowest of K Scores Easy
1991 Find the Middle Index in Array Easy
1995 Count Special Quadruplets Easy
2000 Reverse Prefix of Word Easy
2006 Count Number of Pairs With Absolute Difference K Easy
2011 Final Value of Variable After Performing Operations Easy
2016 Maximum Difference Between Increasing Elements Easy
2022 Convert 1D Array Into 2D Array Easy
2027 Minimum Moves to Convert String Easy
2032 Two Out of Three Easy
2037 Minimum Number of Moves to Seat Everyone Easy
2042 Check if Numbers Are Ascending in a Sentence Easy
2047 Number of Valid Words in a Sentence Easy
2053 Kth Distinct String in an Array Easy
2057 Smallest Index With Equal Value Easy
2062 Count Vowel Substrings of a String Easy
2068 Check Whether Two Strings are Almost Equivalent Easy
2073 Time Needed to Buy Tickets Easy
2085 Count Common Words With One Occurrence Easy
2089 Find Target Indices After Sorting Array Easy
2094 Finding 3-Digit Even Numbers Easy
2099 Find Subsequence of Length K With the Largest Sum Easy
2103 Rings and Rods Easy
2108 Find First Palindromic String in the Array Easy
2114 Maximum Number of Words Found in Sentences Easy
2119 A Number After a Double Reversal Easy
2124 Check if All A's Appears Before All B's Easy
2129 Capitalize the Title Easy
2133 Check if Every Row and Column Contains All Numbers Easy
2144 Minimum Cost of Buying Candies With Discount Easy
2148 Count Elements With Strictly Smaller and Greater Elements Easy
Leetcode Medium Solutions
id Leetcode 772 Medium Solutions Level
2 Add Two Numbers Medium
3 Longest Substring Without Repeating Characters Medium
5 Longest Palindromic Substring Medium
6 Zigzag Conversion Medium
7 Reverse Integer Medium
8 String to Integer (atoi) Medium
11 Container With Most Water Medium
12 Integer to Roman Medium
15 3Sum Medium
16 3Sum Closest Medium
17 Letter Combinations of a Phone Number Medium
18 4Sum Medium
19 Remove Nth Node From End of List Medium
22 Generate Parentheses Medium
24 Swap Nodes in Pairs Medium
29 Divide Two Integers Medium
31 Next Permutation Medium
33 Search in Rotated Sorted Array Medium
34 Find First and Last Position of Element in Sorted Array Medium
36 Valid Sudoku Medium
38 Count and Say Medium
39 Combination Sum Medium
40 Combination Sum II Medium
43 Multiply Strings Medium
45 Jump Game II Medium
46 Permutations Medium
47 Permutations II Medium
48 Rotate Image Medium
49 Group Anagrams Medium
50 Pow(x, n) Medium
54 Spiral Matrix Medium
55 Jump Game Medium
56 Merge Intervals Medium
57 Insert Interval Medium
59 Spiral Matrix II Medium
61 Rotate List Medium
62 Unique Paths Medium
63 Unique Paths II Medium
64 Minimum Path Sum Medium
71 Simplify Path Medium
73 Set Matrix Zeroes Medium
74 Search a 2D Matrix Medium
75 Sort Colors Medium
77 Combinations Medium
78 Subsets Medium
79 Word Search Medium
80 Remove Duplicates from Sorted Array II Medium
81 Search in Rotated Sorted Array II Medium
82 Remove Duplicates from Sorted List II Medium
86 Partition List Medium
89 Gray Code Medium
90 Subsets II Medium
91 Decode Ways Medium
92 Reverse Linked List II Medium
93 Restore IP Addresses Medium
95 Unique Binary Search Trees II Medium
96 Unique Binary Search Trees Medium
97 Interleaving String Medium
98 Validate Binary Search Tree Medium
99 Recover Binary Search Tree Medium
102 Binary Tree Level Order Traversal Medium
103 Binary Tree Zigzag Level Order Traversal Medium
105 Construct Binary Tree from Preorder and Inorder Traversal Medium
106 Construct Binary Tree from Inorder and Postorder Traversal Medium
107 Binary Tree Level Order Traversal II Medium
109 Convert Sorted List to Binary Search Tree Medium
113 Path Sum II Medium
114 Flatten Binary Tree to Linked List Medium
120 Triangle Medium
122 Best Time to Buy and Sell Stock II Medium
128 Longest Consecutive Sequence Medium
129 Sum Root to Leaf Numbers Medium
130 Surrounded Regions Medium
131 Palindrome Partitioning Medium
134 Gas Station Medium
137 Single Number II Medium
139 Word Break Medium
143 Reorder List Medium
146 LRU Cache Medium
147 Insertion Sort List Medium
148 Sort List Medium
150 Evaluate Reverse Polish Notation Medium
151 Reverse Words in a String Medium
152 Maximum Product Subarray Medium
153 Find Minimum in Rotated Sorted Array Medium
156 Binary Tree Upside Down Medium
159 Longest Substring with At Most Two Distinct Characters Medium
161 One Edit Distance Medium
162 Find Peak Element Medium
165 Compare Version Numbers Medium
166 Fraction to Recurring Decimal Medium
172 Factorial Trailing Zeroes Medium
173 Binary Search Tree Iterator Medium
179 Largest Number Medium
186 Reverse Words in a String II Medium
187 Repeated DNA Sequences Medium
189 Rotate Array Medium
198 House Robber Medium
199 Binary Tree Right Side View Medium
200 Number of Islands Medium
201 Bitwise AND of Numbers Range Medium
204 Count Primes Medium
207 Course Schedule Medium
208 Implement Trie (Prefix Tree) Medium
209 Minimum Size Subarray Sum Medium
210 Course Schedule II Medium
211 Design Add and Search Words Data Structure Medium
213 House Robber II Medium
215 Kth Largest Element in an Array Medium
216 Combination Sum III Medium
220 Contains Duplicate III Medium
221 Maximal Square Medium
222 Count Complete Tree Nodes Medium
223 Rectangle Area Medium
227 Basic Calculator II Medium
229 Majority Element II Medium
230 Kth Smallest Element in a BST Medium
236 Lowest Common Ancestor of a Binary Tree Medium
238 Product of Array Except Self Medium
240 Search a 2D Matrix II Medium
241 Different Ways to Add Parentheses Medium
244 Shortest Word Distance II Medium
245 Shortest Word Distance III Medium
247 Strobogrammatic Number II Medium
249 Group Shifted Strings Medium
250 Count Univalue Subtrees Medium
251 Flatten 2D Vector Medium
253 Meeting Rooms II Medium
254 Factor Combinations Medium
255 Verify Preorder Sequence in Binary Search Tree Medium
256 Paint House Medium
259 3Sum Smaller Medium
260 Single Number III Medium
261 Graph Valid Tree Medium
264 Ugly Number II Medium
267 Palindrome Permutation II Medium
271 Encode and Decode Strings Medium
274 H-Index Medium
275 H-Index II Medium
276 Paint Fence Medium
277 Find the Celebrity Medium
279 Perfect Squares Medium
280 Wiggle Sort Medium
281 Zigzag Iterator Medium
285 Inorder Successor in BST Medium
286 Walls and Gates Medium
287 Find the Duplicate Number Medium
288 Unique Word Abbreviation Medium
289 Game of Life Medium
291 Word Pattern II Medium
294 Flip Game II Medium
298 Binary Tree Longest Consecutive Sequence Medium
299 Bulls and Cows Medium
300 Longest Increasing Subsequence Medium
304 Range Sum Query 2D - Immutable Medium
306 Additive Number Medium
307 Range Sum Query - Mutable Medium
309 Best Time to Buy and Sell Stock with Cooldown Medium
310 Minimum Height Trees Medium
311 Sparse Matrix Multiplication Medium
313 Super Ugly Number Medium
314 Binary Tree Vertical Order Traversal Medium
316 Remove Duplicate Letters Medium
318 Maximum Product of Word Lengths Medium
319 Bulb Switcher Medium
320 Generalized Abbreviation Medium
322 Coin Change Medium
323 Number of Connected Components in an Undirected Graph Medium
324 Wiggle Sort II Medium
325 Maximum Size Subarray Sum Equals k Medium
328 Odd Even Linked List Medium
331 Verify Preorder Serialization of a Binary Tree Medium
333 Largest BST Subtree Medium
334 Increasing Triplet Subsequence Medium
337 House Robber III Medium
339 Nested List Weight Sum Medium
340 Longest Substring with At Most K Distinct Characters Medium
341 Flatten Nested List Iterator Medium
343 Integer Break Medium
347 Top K Frequent Elements Medium
348 Design Tic-Tac-Toe Medium
351 Android Unlock Patterns Medium
353 Design Snake Game Medium
355 Design Twitter Medium
356 Line Reflection Medium
357 Count Numbers with Unique Digits Medium
360 Sort Transformed Array Medium
361 Bomb Enemy Medium
362 Design Hit Counter Medium
364 Nested List Weight Sum II Medium
365 Water and Jug Problem Medium
366 Find Leaves of Binary Tree Medium
368 Largest Divisible Subset Medium
369 Plus One Linked List Medium
370 Range Addition Medium
371 Sum of Two Integers Medium
372 Super Pow Medium
373 Find K Pairs with Smallest Sums Medium
375 Guess Number Higher or Lower II Medium
376 Wiggle Subsequence Medium
377 Combination Sum IV Medium
378 Kth Smallest Element in a Sorted Matrix Medium
379 Design Phone Directory Medium
380 Insert Delete GetRandom O(1) Medium
382 Linked List Random Node Medium
384 Shuffle an Array Medium
385 Mini Parser Medium
386 Lexicographical Numbers Medium
388 Longest Absolute File Path Medium
390 Elimination Game Medium
393 UTF-8 Validation Medium
394 Decode String Medium
395 Longest Substring with At Least K Repeating Characters Medium
396 Rotate Function Medium
397 Integer Replacement Medium
398 Random Pick Index Medium
399 Evaluate Division Medium
400 Nth Digit Medium
402 Remove K Digits Medium
406 Queue Reconstruction by Height Medium
413 Arithmetic Slices Medium
416 Partition Equal Subset Sum Medium
417 Pacific Atlantic Water Flow Medium
418 Sentence Screen Fitting Medium
419 Battleships in a Board Medium
421 Maximum XOR of Two Numbers in an Array Medium
423 Reconstruct Original Digits from English Medium
424 Longest Repeating Character Replacement Medium
433 Minimum Genetic Mutation Medium
435 Non-overlapping Intervals Medium
436 Find Right Interval Medium
437 Path Sum III Medium
438 Find All Anagrams in a String Medium
439 Ternary Expression Parser Medium
442 Find All Duplicates in an Array Medium
443 String Compression Medium
444 Sequence Reconstruction Medium
445 Add Two Numbers II Medium
447 Number of Boomerangs Medium
449 Serialize and Deserialize BST Medium
450 Delete Node in a BST Medium
451 Sort Characters By Frequency Medium
452 Minimum Number of Arrows to Burst Balloons Medium
453 Minimum Moves to Equal Array Elements Medium
454 4Sum II Medium
456 132 Pattern Medium
457 Circular Array Loop Medium
462 Minimum Moves to Equal Array Elements II Medium
464 Can I Win Medium
467 Unique Substrings in Wraparound String Medium
468 Validate IP Address Medium
469 Convex Polygon Medium
470 Implement Rand10() Using Rand7() Medium
473 Matchsticks to Square Medium
474 Ones and Zeroes Medium
475 Heaters Medium
477 Total Hamming Distance Medium
478 Generate Random Point in a Circle Medium
481 Magical String Medium
484 Find Permutation Medium
486 Predict the Winner Medium
487 Max Consecutive Ones II Medium
490 The Maze Medium
491 Increasing Subsequences Medium
494 Target Sum Medium
497 Random Point in Non-overlapping Rectangles Medium
498 Diagonal Traverse Medium
503 Next Greater Element II Medium
505 The Maze II Medium
508 Most Frequent Subtree Sum Medium
513 Find Bottom Left Tree Value Medium
515 Find Largest Value in Each Tree Row Medium
516 Longest Palindromic Subsequence Medium
518 Coin Change 2 Medium
519 Random Flip Matrix Medium
522 Longest Uncommon Subsequence II Medium
523 Continuous Subarray Sum Medium
524 Longest Word in Dictionary through Deleting Medium
525 Contiguous Array Medium
526 Beautiful Arrangement Medium
528 Random Pick with Weight Medium
529 Minesweeper Medium
531 Lonely Pixel I Medium
532 K-diff Pairs in an Array Medium
533 Lonely Pixel II Medium
535 Encode and Decode TinyURL Medium
536 Construct Binary Tree from String Medium
537 Complex Number Multiplication Medium
538 Convert BST to Greater Tree Medium
539 Minimum Time Difference Medium
540 Single Element in a Sorted Array Medium
542 01 Matrix Medium
544 Output Contest Matches Medium
545 Boundary of Binary Tree Medium
547 Number of Provinces Medium
549 Binary Tree Longest Consecutive Sequence II Medium
553 Optimal Division Medium
554 Brick Wall Medium
555 Split Concatenated Strings Medium
556 Next Greater Element III Medium
560 Subarray Sum Equals K Medium
562 Longest Line of Consecutive One in Matrix Medium
565 Array Nesting Medium
567 Permutation in String Medium
573 Squirrel Simulation Medium
576 Out of Boundary Paths Medium
581 Shortest Unsorted Continuous Subarray Medium
582 Kill Process Medium
583 Delete Operation for Two Strings Medium
592 Fraction Addition and Subtraction Medium
593 Valid Square Medium
609 Find Duplicate File in System Medium
611 Valid Triangle Number Medium
616 Add Bold Tag in String Medium
621 Task Scheduler Medium
622 Design Circular Queue Medium
623 Add One Row to Tree Medium
624 Maximum Distance in Arrays Medium
625 Minimum Factorization Medium
633 Sum of Square Numbers Medium
634 Find the Derangement of An Array Medium
635 Design Log Storage System Medium
636 Exclusive Time of Functions Medium
638 Shopping Offers Medium
640 Solve the Equation Medium
641 Design Circular Deque Medium
646 Maximum Length of Pair Chain Medium
647 Palindromic Substrings Medium
648 Replace Words Medium
649 Dota2 Senate Medium
650 2 Keys Keyboard Medium
651 4 Keys Keyboard Medium
652 Find Duplicate Subtrees Medium
654 Maximum Binary Tree Medium
655 Print Binary Tree Medium
658 Find K Closest Elements Medium
659 Split Array into Consecutive Subsequences Medium
662 Maximum Width of Binary Tree Medium
663 Equal Tree Partition Medium
665 Non-decreasing Array Medium
666 Path Sum IV Medium
667 Beautiful Arrangement II Medium
669 Trim a Binary Search Tree Medium
670 Maximum Swap Medium
672 Bulb Switcher II Medium
673 Number of Longest Increasing Subsequence Medium
676 Implement Magic Dictionary Medium
677 Map Sum Pairs Medium
678 Valid Parenthesis String Medium
681 Next Closest Time Medium
684 Redundant Connection Medium
686 Repeated String Match Medium
687 Longest Univalue Path Medium
688 Knight Probability in Chessboard Medium
692 Top K Frequent Words Medium
694 Number of Distinct Islands Medium
695 Max Area of Island Medium
698 Partition to K Equal Sum Subsets Medium
701 Insert into a Binary Search Tree Medium
707 Design Linked List Medium
712 Minimum ASCII Delete Sum for Two Strings Medium
713 Subarray Product Less Than K Medium
714 Best Time to Buy and Sell Stock with Transaction Fee Medium
718 Maximum Length of Repeated Subarray Medium
720 Longest Word in Dictionary Medium
721 Accounts Merge Medium
722 Remove Comments Medium
723 Candy Crush Medium
725 Split Linked List in Parts Medium
729 My Calendar I Medium
731 My Calendar II Medium
735 Asteroid Collision Medium
737 Sentence Similarity II Medium
738 Monotone Increasing Digits Medium
739 Daily Temperatures Medium
740 Delete and Earn Medium
742 Closest Leaf in a Binary Tree Medium
743 Network Delay Time Medium
750 Number Of Corner Rectangles Medium
751 IP to CIDR Medium
752 Open the Lock Medium
754 Reach a Number Medium
755 Pour Water Medium
756 Pyramid Transition Matrix Medium
758 Bold Words in String Medium
763 Partition Labels Medium
764 Largest Plus Sign Medium
767 Reorganize String Medium
769 Max Chunks To Make Sorted Medium
775 Global and Local Inversions Medium
776 Split BST Medium
777 Swap Adjacent in LR String Medium
779 K-th Symbol in Grammar Medium
781 Rabbits in Forest Medium
784 Letter Case Permutation Medium
785 Is Graph Bipartite? Medium
787 Cheapest Flights Within K Stops Medium
788 Rotated Digits Medium
789 Escape The Ghosts Medium
790 Domino and Tromino Tiling Medium
791 Custom Sort String Medium
792 Number of Matching Subsequences Medium
794 Valid Tic-Tac-Toe State Medium
795 Number of Subarrays with Bounded Maximum Medium
797 All Paths From Source to Target Medium
799 Champagne Tower Medium
802 Find Eventual Safe States Medium
807 Max Increase to Keep City Skyline Medium
808 Soup Servings Medium
809 Expressive Words Medium
811 Subdomain Visit Count Medium
813 Largest Sum of Averages Medium
814 Binary Tree Pruning Medium
816 Ambiguous Coordinates Medium
817 Linked List Components Medium
820 Short Encoding of Words Medium
822 Card Flipping Game Medium
823 Binary Trees With Factors Medium
825 Friends Of Appropriate Ages Medium
826 Most Profit Assigning Work Medium
831 Masking Personal Information Medium
833 Find And Replace in String Medium
835 Image Overlap Medium
837 New 21 Game Medium
838 Push Dominoes Medium
840 Magic Squares In Grid Medium
841 Keys and Rooms Medium
842 Split Array into Fibonacci Sequence Medium
845 Longest Mountain in Array Medium
846 Hand of Straights Medium
848 Shifting Letters Medium
849 Maximize Distance to Closest Person Medium
851 Loud and Rich Medium
853 Car Fleet Medium
855 Exam Room Medium
856 Score of Parentheses Medium
858 Mirror Reflection Medium
861 Score After Flipping Matrix Medium
863 All Nodes Distance K in Binary Tree Medium
865 Smallest Subtree with all the Deepest Nodes Medium
866 Prime Palindrome Medium
869 Reordered Power of 2 Medium
870 Advantage Shuffle Medium
873 Length of Longest Fibonacci Subsequence Medium
874 Walking Robot Simulation Medium
875 Koko Eating Bananas Medium
877 Stone Game Medium
880 Decoded String at Index Medium
881 Boats to Save People Medium
885 Spiral Matrix III Medium
886 Possible Bipartition Medium
889 Construct Binary Tree from Preorder and Postorder Traversal Medium
890 Find and Replace Pattern Medium
893 Groups of Special-Equivalent Strings Medium
894 All Possible Full Binary Trees Medium
898 Bitwise ORs of Subarrays Medium
900 RLE Iterator Medium
901 Online Stock Span Medium
904 Fruit Into Baskets Medium
907 Sum of Subarray Minimums Medium
909 Snakes and Ladders Medium
910 Smallest Range II Medium
911 Online Election Medium
912 Sort an Array Medium
915 Partition Array into Disjoint Intervals Medium
916 Word Subsets Medium
918 Maximum Sum Circular Subarray Medium
919 Complete Binary Tree Inserter Medium
921 Minimum Add to Make Parentheses Valid Medium
923 3Sum With Multiplicity Medium
926 Flip String to Monotone Increasing Medium
930 Binary Subarrays With Sum Medium
931 Minimum Falling Path Sum Medium
932 Beautiful Array Medium
934 Shortest Bridge Medium
935 Knight Dialer Medium
939 Minimum Area Rectangle Medium
945 Minimum Increment to Make Array Unique Medium
946 Validate Stack Sequences Medium
947 Most Stones Removed with Same Row or Column Medium
948 Bag of Tokens Medium
949 Largest Time for Given Digits Medium
950 Reveal Cards In Increasing Order Medium
951 Flip Equivalent Binary Trees Medium
954 Array of Doubled Pairs Medium
955 Delete Columns to Make Sorted II Medium
957 Prison Cells After N Days Medium
958 Check Completeness of a Binary Tree Medium
959 Regions Cut By Slashes Medium
962 Maximum Width Ramp Medium
963 Minimum Area Rectangle II Medium
966 Vowel Spellchecker Medium
967 Numbers With Same Consecutive Differences Medium
969 Pancake Sorting Medium
970 Powerful Integers Medium
971 Flip Binary Tree To Match Preorder Traversal Medium
973 K Closest Points to Origin Medium
974 Subarray Sums Divisible by K Medium
978 Longest Turbulent Subarray Medium
979 Distribute Coins in Binary Tree Medium
981 Time Based Key-Value Store Medium
983 Minimum Cost For Tickets Medium
984 String Without AAA or BBB Medium
985 Sum of Even Numbers After Queries Medium
986 Interval List Intersections Medium
988 Smallest String Starting From Leaf Medium
990 Satisfiability of Equality Equations Medium
991 Broken Calculator Medium
994 Rotting Oranges Medium
998 Maximum Binary Tree II Medium
1003 Check If Word Is Valid After Substitutions Medium
1004 Max Consecutive Ones III Medium
1006 Clumsy Factorial Medium
1007 Minimum Domino Rotations For Equal Row Medium
1008 Construct Binary Search Tree from Preorder Traversal Medium
1010 Pairs of Songs With Total Durations Divisible by 60 Medium
1011 Capacity To Ship Packages Within D Days Medium
1014 Best Sightseeing Pair Medium
1015 Smallest Integer Divisible by K Medium
1016 Binary String With Substrings Representing 1 To N Medium
1017 Convert to Base -2 Medium
1019 Next Greater Node In Linked List Medium
1020 Number of Enclaves Medium
1023 Camelcase Matching Medium
1024 Video Stitching Medium
1026 Maximum Difference Between Node and Ancestor Medium
1027 Longest Arithmetic Subsequence Medium
1029 Two City Scheduling Medium
1031 Maximum Sum of Two Non-Overlapping Subarrays Medium
1033 Moving Stones Until Consecutive Medium
1034 Coloring A Border Medium
1035 Uncrossed Lines Medium
1038 Binary Search Tree to Greater Sum Tree Medium
1039 Minimum Score Triangulation of Polygon Medium
1040 Moving Stones Until Consecutive II Medium
1041 Robot Bounded In Circle Medium
1042 Flower Planting With No Adjacent Medium
1043 Partition Array for Maximum Sum Medium
1048 Longest String Chain Medium
1049 Last Stone Weight II Medium
1052 Grumpy Bookstore Owner Medium
1053 Previous Permutation With One Swap Medium
1054 Distant Barcodes Medium
1055 Shortest Way to Form String Medium
1057 Campus Bikes Medium
1058 Minimize Rounding Error to Meet Target Medium
1059 All Paths from Source Lead to Destination Medium
1060 Missing Element in Sorted Array Medium
1061 Lexicographically Smallest Equivalent String Medium
1062 Longest Repeating Substring Medium
1066 Campus Bikes II Medium
1072 Flip Columns For Maximum Number of Equal Rows Medium
1073 Adding Two Negabinary Numbers Medium
1079 Letter Tile Possibilities Medium
1080 Insufficient Nodes in Root to Leaf Paths Medium
1081 Smallest Subsequence of Distinct Characters Medium
1087 Brace Expansion Medium
1090 Largest Values From Labels Medium
1091 Shortest Path in Binary Matrix Medium
1093 Statistics from a Large Sample Medium
1094 Car Pooling Medium
1100 Find K-Length Substrings With No Repeated Characters Medium
1101 The Earliest Moment When Everyone Become Friends Medium
1102 Path With Maximum Minimum Value Medium
1104 Path In Zigzag Labelled Binary Tree Medium
1105 Filling Bookcase Shelves Medium
1109 Corporate Flight Bookings Medium
1110 Delete Nodes And Return Forest Medium
1111 Maximum Nesting Depth of Two Valid Parentheses Strings Medium
1116 Print Zero Even Odd Medium
1117 Building H2O Medium
1120 Maximum Average Subtree Medium
1123 Lowest Common Ancestor of Deepest Leaves Medium
1124 Longest Well-Performing Interval Medium
1129 Shortest Path with Alternating Colors Medium
1130 Minimum Cost Tree From Leaf Values Medium
1131 Maximum of Absolute Value Expression Medium
1135 Connecting Cities With Minimum Cost Medium
1136 Parallel Courses Medium
1138 Alphabet Board Path Medium
1139 Largest 1-Bordered Square Medium
1140 Stone Game II Medium
1143 Longest Common Subsequence Medium
1144 Decrease Elements To Make Array Zigzag Medium
1145 Binary Tree Coloring Game Medium
1146 Snapshot Array Medium
1151 Minimum Swaps to Group All 1's Together Medium
1152 Analyze User Website Visit Pattern Medium
1155 Number of Dice Rolls With Target Sum Medium
1156 Swap For Longest Repeated Character Substring Medium
1161 Maximum Level Sum of a Binary Tree Medium
1162 As Far from Land as Possible Medium
1166 Design File System Medium
1167 Minimum Cost to Connect Sticks Medium
1169 Invalid Transactions Medium
1170 Compare Strings by Frequency of the Smallest Character Medium
1171 Remove Zero Sum Consecutive Nodes from Linked List Medium
1177 Can Make Palindrome from Substring Medium
1181 Before and After Puzzle Medium
1182 Shortest Distance to Target Color Medium
1186 Maximum Subarray Sum with One Deletion Medium
1188 Design Bounded Blocking Queue Medium
1190 Reverse Substrings Between Each Pair of Parentheses Medium
1191 K-Concatenation Maximum Sum Medium
1195 Fizz Buzz Multithreaded Medium
1197 Minimum Knight Moves Medium
1198 Find Smallest Common Element in All Rows Medium
1201 Ugly Number III Medium
1202 Smallest String With Swaps Medium
1208 Get Equal Substrings Within Budget Medium
1209 Remove All Adjacent Duplicates in String II Medium
1214 Two Sum BSTs Medium
1215 Stepping Numbers Medium
1218 Longest Arithmetic Subsequence of Given Difference Medium
1219 Path with Maximum Gold Medium
1222 Queens That Can Attack the King Medium
1226 The Dining Philosophers Medium
1227 Airplane Seat Assignment Probability Medium
1229 Meeting Scheduler Medium
1230 Toss Strange Coins Medium
1233 Remove Sub-Folders from the Filesystem Medium
1234 Replace the Substring for Balanced String Medium
1237 Find Positive Integer Solution for a Given Equation Medium
1238 Circular Permutation in Binary Representation Medium
1239 Maximum Length of a Concatenated String with Unique Characters Medium
1242 Web Crawler Multithreaded Medium
1244 Design A Leaderboard Medium
1245 Tree Diameter Medium
1247 Minimum Swaps to Make Strings Equal Medium
1248 Count Number of Nice Subarrays Medium
1249 Minimum Remove to Make Valid Parentheses Medium
1253 Reconstruct a 2-Row Binary Matrix Medium
1254 Number of Closed Islands Medium
1256 Encode Number Medium
1257 Smallest Common Region Medium
1258 Synonymous Sentences Medium
1261 Find Elements in a Contaminated Binary Tree Medium
1262 Greatest Sum Divisible by Three Medium
1265 Print Immutable Linked List in Reverse Medium
1267 Count Servers that Communicate Medium
1268 Search Suggestions System Medium
1272 Remove Interval Medium
1273 Delete Tree Nodes Medium
1276 Number of Burgers with No Waste of Ingredients Medium
1277 Count Square Submatrices with All Ones Medium
1282 Group the People Given the Group Size They Belong To Medium
1283 Find the Smallest Divisor Given a Threshold Medium
1286 Iterator for Combination Medium
1288 Remove Covered Intervals Medium
1291 Sequential Digits Medium
1292 Maximum Side Length of a Square with Sum Less than or Equal to Threshold Medium
1296 Divide Array in Sets of K Consecutive Numbers Medium
1297 Maximum Number of Occurrences of a Substring Medium
1300 Sum of Mutated Array Closest to Target Medium
1302 Deepest Leaves Sum Medium
1305 All Elements in Two Binary Search Trees Medium
1306 Jump Game III Medium
1310 XOR Queries of a Subarray Medium
1311 Get Watched Videos by Your Friends Medium
1314 Matrix Block Sum Medium
1315 Sum of Nodes with Even-Valued Grandparent Medium
1318 Minimum Flips to Make a OR b Equal to c Medium
1319 Number of Operations to Make Network Connected Medium
1324 Print Words Vertically Medium
1325 Delete Leaves With a Given Value Medium
1328 Break a Palindrome Medium
1329 Sort the Matrix Diagonally Medium
1333 Filter Restaurants by Vegan-Friendly, Price and Distance Medium
1334 Find the City With the Smallest Number of Neighbors at a Threshold Distance Medium
1338 Reduce Array Size to The Half Medium
1339 Maximum Product of Splitted Binary Tree Medium
1343 Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold Medium
1344 Angle Between Hands of a Clock Medium
1347 Minimum Number of Steps to Make Two Strings Anagram Medium
1348 Tweet Counts Per Frequency Medium
1352 Product of the Last K Numbers Medium
1353 Maximum Number of Events That Can Be Attended Medium
1357 Apply Discount Every n Orders Medium
1358 Number of Substrings Containing All Three Characters Medium
1361 Validate Binary Tree Nodes Medium
1362 Closest Divisors Medium
1366 Rank Teams by Votes Medium
1367 Linked List in Binary Tree Medium
1371 Find the Longest Substring Containing Vowels in Even Counts Medium
1372 Longest ZigZag Path in a Binary Tree Medium
1375 Number of Times Binary String Is Prefix-Aligned Medium
1376 Time Needed to Inform All Employees Medium
1381 Design a Stack With Increment Operation Medium
1382 Balance a Binary Search Tree Medium
1386 Cinema Seat Allocation Medium
1387 Sort Integers by The Power Value Medium
1390 Four Divisors Medium
1391 Check if There is a Valid Path in a Grid Medium
1395 Count Number of Teams Medium
1396 Design Underground System Medium
1428 Leftmost Column with at Least a One Medium
1533 Find the Index of the Large Integer Medium
1538 Guess the Majority in a Hidden Array Medium
1631 Path With Minimum Effort Medium
1637 Widest Vertical Area Between Two Points Containing No Points Medium
1638 Count Substrings That Differ by One Character Medium
1641 Count Sorted Vowel Strings Medium
1642 Furthest Building You Can Reach Medium
1647 Minimum Deletions to Make Character Frequencies Unique Medium
1648 Sell Diminishing-Valued Colored Balls Medium
1653 Minimum Deletions to Make String Balanced Medium
1654 Minimum Jumps to Reach Home Medium
1657 Determine if Two Strings Are Close Medium
1658 Minimum Operations to Reduce X to Zero Medium
1669 Merge In Between Linked Lists Medium
1670 Design Front Middle Back Queue Medium
1673 Find the Most Competitive Subsequence Medium
1674 Minimum Moves to Make Array Complementary Medium
1679 Max Number of K-Sum Pairs Medium
1680 Concatenation of Consecutive Binary Numbers Medium
1682 Longest Palindromic Subsequence II Medium
1685 Sum of Absolute Differences in a Sorted Array Medium
1686 Stone Game VI Medium
1689 Partitioning Into Minimum Number Of Deci-Binary Numbers Medium
1690 Stone Game VII Medium
1695 Maximum Erasure Value Medium
1696 Jump Game VI Medium
1698 Number of Distinct Substrings in a String Medium
1701 Average Waiting Time Medium
1702 Maximum Binary String After Change Medium
1705 Maximum Number of Eaten Apples Medium
1706 Where Will the Ball Fall Medium
1711 Count Good Meals Medium
1712 Ways to Split Array Into Three Subarrays Medium
1717 Maximum Score From Removing Substrings Medium
1718 Construct the Lexicographically Largest Valid Sequence Medium
1721 Swapping Nodes in a Linked List Medium
1722 Minimize Hamming Distance After Swap Operations Medium
1726 Tuple with Same Product Medium
1727 Largest Submatrix With Rearrangements Medium
1730 Shortest Path to Get Food Medium
1733 Minimum Number of People to Teach Medium
1734 Decode XORed Permutation Medium
1737 Change Minimum Characters to Satisfy One of Three Conditions Medium
1738 Find Kth Largest XOR Coordinate Value Medium
1740 Find Distance in a Binary Tree Medium
1746 Maximum Subarray Sum After One Operation Medium
1749 Maximum Absolute Sum of Any Subarray Medium
1750 Minimum Length of String After Deleting Similar Ends Medium
1753 Maximum Score From Removing Stones Medium
1754 Largest Merge Of Two Strings Medium
1760 Minimum Limit of Balls in a Bag Medium
1762 Buildings With an Ocean View Medium
1769 Minimum Number of Operations to Move All Balls to Each Box Medium
1792 Maximum Average Pass Ratio Medium
1794 Count Pairs of Equal Substrings With Minimum Difference Medium
1797 Design Authentication Manager Medium
1798 Maximum Number of Consecutive Values You Can Make Medium
1801 Number of Orders in the Backlog Medium
1802 Maximum Value at a Given Index in a Bounded Array Medium
1804 Implement Trie II (Prefix Tree) Medium
1806 Minimum Number of Operations to Reinitialize a Permutation Medium
1807 Evaluate the Bracket Pairs of a String Medium
1810 Minimum Path Cost in a Hidden Grid Medium
1813 Sentence Similarity III Medium
1814 Count Nice Pairs in an Array Medium
1817 Finding the Users Active Minutes Medium
1818 Minimum Absolute Sum Difference Medium
1820 Maximum Number of Accepted Invitations Medium
1823 Find the Winner of the Circular Game Medium
1824 Minimum Sideway Jumps Medium
1828 Queries on Number of Points Inside a Circle Medium
1829 Maximum XOR for Each Query Medium
1833 Maximum Ice Cream Bars Medium
1836 Remove Duplicates From an Unsorted Linked List Medium
1838 Frequency of the Most Frequent Element Medium
1839 Longest Substring Of All Vowels in Order Medium
Leetcode Hard Solutions
id Leetcode 211 Hard Solutions Level
4 Median of Two Sorted Arrays Hard
10 Regular Expression Matching Hard
23 Merge k Sorted Lists Hard
25 Reverse Nodes in k-Group Hard
30 Substring with Concatenation of All Words Hard
32 Longest Valid Parentheses Hard
37 Sudoku Solver Hard
41 First Missing Positive Hard
42 Trapping Rain Water Hard
44 Wildcard Matching Hard
51 N-Queens Hard
52 N-Queens II Hard
60 Permutation Sequence Hard
65 Valid Number Hard
68 Text Justification Hard
72 Edit Distance Hard
76 Minimum Window Substring Hard
84 Largest Rectangle in Histogram Hard
85 Maximal Rectangle Hard
87 Scramble String Hard
115 Distinct Subsequences Hard
123 Best Time to Buy and Sell Stock III Hard
124 Binary Tree Maximum Path Sum Hard
126 Word Ladder II Hard
127 Word Ladder Hard
132 Palindrome Partitioning II Hard
135 Candy Hard
140 Word Break II Hard
149 Max Points on a Line Hard
154 Find Minimum in Rotated Sorted Array II Hard
164 Maximum Gap Hard
174 Dungeon Game Hard
188 Best Time to Buy and Sell Stock IV Hard
212 Word Search II Hard
214 Shortest Palindrome Hard
218 The Skyline Problem Hard
224 Basic Calculator Hard
233 Number of Digit One Hard
239 Sliding Window Maximum Hard
248 Strobogrammatic Number III Hard
265 Paint House II Hard
269 Alien Dictionary Hard
272 Closest Binary Search Tree Value II Hard
273 Integer to English Words Hard
282 Expression Add Operators Hard
295 Find Median from Data Stream Hard
296 Best Meeting Point Hard
297 Serialize and Deserialize Binary Tree Hard
301 Remove Invalid Parentheses Hard
302 Smallest Rectangle Enclosing Black Pixels Hard
305 Number of Islands II Hard
312 Burst Balloons Hard
315 Count of Smaller Numbers After Self Hard
317 Shortest Distance from All Buildings Hard
321 Create Maximum Number Hard
329 Longest Increasing Path in a Matrix Hard
330 Patching Array Hard
332 Reconstruct Itinerary Hard
336 Palindrome Pairs Hard
352 Data Stream as Disjoint Intervals Hard
354 Russian Doll Envelopes Hard
358 Rearrange String k Distance Apart Hard
363 Max Sum of Rectangle No Larger Than K Hard
381 Insert Delete GetRandom O(1) - Duplicates allowed Hard
391 Perfect Rectangle Hard
403 Frog Jump Hard
407 Trapping Rain Water II Hard
410 Split Array Largest Sum Hard
411 Minimum Unique Word Abbreviation Hard
420 Strong Password Checker Hard
425 Word Squares Hard
432 All O`one Data Structure Hard
440 K-th Smallest in Lexicographical Order Hard
446 Arithmetic Slices II - Subsequence Hard
458 Poor Pigs Hard
460 LFU Cache Hard
465 Optimal Account Balancing Hard
471 Encode String with Shortest Length Hard
472 Concatenated Words Hard
479 Largest Palindrome Product Hard
480 Sliding Window Median Hard
488 Zuma Game Hard
493 Reverse Pairs Hard
499 The Maze III Hard
502 IPO Hard
514 Freedom Trail Hard
517 Super Washing Machines Hard
527 Word Abbreviation Hard
546 Remove Boxes Hard
548 Split Array with Equal Sum Hard
552 Student Attendance Record II Hard
564 Find the Closest Palindrome Hard
568 Maximum Vacation Days Hard
588 Design In-Memory File System Hard
591 Tag Validator Hard
630 Course Schedule III Hard
631 Design Excel Sum Formula Hard
632 Smallest Range Covering Elements from K Lists Hard
642 Design Search Autocomplete System Hard
660 Remove 9 Hard
668 Kth Smallest Number in Multiplication Table Hard
675 Cut Off Trees for Golf Event Hard
679 24 Game Hard
683 K Empty Slots Hard
689 Maximum Sum of 3 Non-Overlapping Subarrays Hard
710 Random Pick with Blacklist Hard
719 Find K-th Smallest Pair Distance Hard
726 Number of Atoms Hard
727 Minimum Window Subsequence Hard
732 My Calendar III Hard
736 Parse Lisp Expression Hard
753 Cracking the Safe Hard
759 Employee Free Time Hard
761 Special Binary String Hard
765 Couples Holding Hands Hard
768 Max Chunks To Make Sorted II Hard
770 Basic Calculator IV Hard
772 Basic Calculator III Hard
773 Sliding Puzzle Hard
774 Minimize Max Distance to Gas Station Hard
778 Swim in Rising Water Hard
780 Reaching Points Hard
786 K-th Smallest Prime Fraction Hard
801 Minimum Swaps To Make Sequences Increasing Hard
805 Split Array With Same Average Hard
810 Chalkboard XOR Game Hard
815 Bus Routes Hard
818 Race Car Hard
827 Making A Large Island Hard
828 Count Unique Characters of All Substrings of a Given String Hard
829 Consecutive Numbers Sum Hard
843 Guess the Word Hard
847 Shortest Path Visiting All Nodes Hard
854 K-Similar Strings Hard
857 Minimum Cost to Hire K Workers Hard
862 Shortest Subarray with Sum at Least K Hard
871 Minimum Number of Refueling Stops Hard
891 Sum of Subsequence Widths Hard
895 Maximum Frequency Stack Hard
899 Orderly Queue Hard
903 Valid Permutations for DI Sequence Hard
924 Minimize Malware Spread Hard
960 Delete Columns to Make Sorted III Hard
972 Equal Rational Numbers Hard
980 Unique Paths III Hard
982 Triples with Bitwise AND Equal To Zero Hard
987 Vertical Order Traversal of a Binary Tree Hard
992 Subarrays with K Different Integers Hard
995 Minimum Number of K Consecutive Bit Flips Hard
1028 Recover a Tree From Preorder Traversal Hard
1032 Stream of Characters Hard
1036 Escape a Large Maze Hard
1044 Longest Duplicate Substring Hard
1063 Number of Valid Subarrays Hard
1074 Number of Submatrices That Sum to Target Hard
1092 Shortest Common Supersequence Hard
1096 Brace Expansion II Hard
1106 Parsing A Boolean Expression Hard
1121 Divide Array Into Increasing Sequences Hard
1147 Longest Chunked Palindrome Decomposition Hard
1163 Last Substring in Lexicographical Order Hard
1168 Optimize Water Distribution in a Village Hard
1172 Dinner Plate Stacks Hard
1183 Maximum Number of Ones Hard
1192 Critical Connections in a Network Hard
1206 Design Skiplist Hard
1210 Minimum Moves to Reach Target with Rotations Hard
1216 Valid Palindrome III Hard
1220 Count Vowels Permutation Hard
1223 Dice Roll Simulation Hard
1224 Maximum Equal Frequency Hard
1231 Divide Chocolate Hard
1235 Maximum Profit in Job Scheduling Hard
1240 Tiling a Rectangle with the Fewest Squares Hard
1246 Palindrome Removal Hard
1250 Check If It Is a Good Array Hard
1255 Maximum Score Words Formed by Letters Hard
1259 Handshakes That Don't Cross Hard
1263 Minimum Moves to Move a Box to Their Target Location Hard
1274 Number of Ships in a Rectangle Hard
1278 Palindrome Partitioning III Hard
1284 Minimum Number of Flips to Convert Binary Matrix to Zero Matrix Hard
1289 Minimum Falling Path Sum II Hard
1293 Shortest Path in a Grid with Obstacles Elimination Hard
1298 Maximum Candies You Can Get from Boxes Hard
1312 Minimum Insertion Steps to Make a String Palindrome Hard
1316 Distinct Echo Substrings Hard
1320 Minimum Distance to Type a Word Using Two Fingers Hard
1326 Minimum Number of Taps to Open to Water a Garden Hard
1330 Reverse Subarray To Maximize Array Value Hard
1335 Minimum Difficulty of a Job Schedule Hard
1340 Jump Game V Hard
1359 Count All Valid Pickup and Delivery Options Hard
1368 Minimum Cost to Make at Least One Valid Path in a Grid Hard
1377 Frog Position After T Seconds Hard
1383 Maximum Performance of a Team Hard
1458 Max Dot Product of Two Subsequences Hard
1494 Parallel Courses II Hard
1499 Max Value of Equation Hard
1531 String Compression II Hard
1591 Strange Printer II Hard
1611 Minimum One Bit Operations to Make Integers Zero Hard
1617 Count Subtrees With Max Distance Between Cities Hard
1643 Kth Smallest Instructions Hard
1659 Maximize Grid Happiness Hard
1671 Minimum Number of Removals to Make Mountain Array Hard
1681 Minimum Incompatibility Hard
1691 Maximum Height by Stacking Cuboids Hard
1692 Count Ways to Distribute Candies Hard
1697 Checking Existence of Edge Length Limited Paths Hard
1713 Minimum Operations to Make a Subsequence Hard