LeetCode-Record

A record for coding practice on leetcode. Notation '*' means appearing the second time.

Ⅰ Basic Algorithm

leetcode题目	Python代码	C++代码	难度
(iteratively+recursively)206. Reverse Linked List	reverse-linked-list	reverse-linked-list	Easy
(suffix sum)848. Shifting Letters	shifting-letters		Medium
(iteratively+recursively)1137. N-th Tribonacci Number	n-th-tribonacci-number	n-th-tribonacci-number	Easy
(preorder traversal)543. Diameter of Binary Tree	diameter-of-binary-tree		Easy
(binary search)374. Guess Number Higher or Lower	guess-number-higher-or-lower	guess-number-higher-or-lower	Easy
(binary search)1008. Construct Binary Search Tree from Preorder Traversal	construct-binary-search-tree-from-preorder-traversal		Medium
(binary search)993. Cousins in Binary Tree	cousins-in-binary-tree		Easy
(complete binary search)222. Count Complete Tree Nodes	count-complete-tree-nodes	count-complete-tree-nodes	Medium
(traversal)404. Sum of Left Leaves	sum-of-left-leaves		Easy
(binary search)441. Arranging Coins	arranging-coins		Easy
(bitmask)1286. Iterator for Combination	iterator-for-combination		Medium
(In-place modification)448. Find All Numbers Disappeared in an Array	find-all-numbers-disappeared-in-an-array		Easy
(binary search)106. Construct Binary Tree from Inorder and Postorder Traversal	construct-binary-tree-from-inorder-and-postorder-traversal	construct-binary-tree-from-inorder-and-postorder-traversal	Medium
(binary search tree)450. Delete Node in a BST	delete-node-in-a-bst		Medium
(binary search)35. Search Insert Position	search-insert-position	search-insert-position	Easy
(pre&suf product)238. Product of Array Except Self	product-of-array-except-self		Medium
(quick sort)148. Sort List	sort-list	sort-list	Medium
(lowbit)231. Power of Two	power-of-two		Easy
(prefix sum)1094. Car Pooling		car-pooling	Medium
(binary search tree)701. Insert into a Binary Search Tree		insert-into-a-binary-search-tree	Medium
(binary search)875. Koko Eating Bananas		koko-eating-bananas	Medium
(binary search)704. Binary Search		binary-search	Easy
(binary search)81. Search in Rotated Sorted Array II		search-in-rotated-sorted-array-ii	Medium
(2-D binary search)74. Search a 2D Matrix		search-a-2d-matrix	Medium
(binary search tree)669. Trim a Binary Search Tree		trim-a-binary-search-tree	Medium
(sorting)581. Shortest Unsorted Continuous Subarray		shortest-unsorted-continuous-subarray	Medium
215. Kth Largest Element in an Array		kth-largest-element-in-an-array	Medium
665. Non-decreasing Array		non-decreasing-array	Medium
1423. Maximum Points You Can Obtain from Cards		maximum-points-you-can-obtain-from-cards	Medium
(sort)1710. Maximum Units on a Truck		maximum-units-on-a-truck	Easy
(sort)1465. Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts		maximum-area-of-a-piece-of-cake-after-horizontal-and-vertical-cuts	Medium
376. Wiggle Subsequence		wiggle-subsequence	Medium
(merge sort)315. Count of Smaller Numbers After Self		count-of-smaller-numbers-after-self	Hard
(binary search)34. Find First and Last Position of Element in Sorted Array		find-first-and-last-position-of-element-in-sorted-array	Medium
(sort)451. Sort Characters By Frequency	sort-characters-by-frequency	sort-characters-by-frequency	Medium
(sort)953. Verifying an Alien Dictionary		verifying-an-alien-dictionary	Easy
(binary search)1011. Capacity To Ship Packages Within D Days		capacity-to-ship-packages-within-d-days	Medium
(sort)912. Sort an Array		sort-an-array	Medium
(binary search)2187. Minimum Time to Complete Trips		minimum-time-to-complete-trips	Medium

1 one Pointer

leetcode题目	Python代码	C++代码	难度
978. Longest Turbulent Subarray	longest-turbulent-subarray		Medium
55. Jump Game	jump-game	jump-game	Medium
(segment tree)53. Maximum Subarray	maximum-subarray	maximum-subarray	Easy
645. Set Mismatch		set-mismatch	Easy

2 Two Pointers

leetcode题目	Python代码	C++代码	难度
917. Reverse Only Letters	reverse-only-letters		Easy
922. Sort Array By Parity II	sort-array-by-parity-ii		Easy
75. Sort Colors	sort-colors		Medium
(more than 2)328. Odd Even Linked List	odd-even-linked-list	odd-even-linked-list	Medium
876. Middle of the Linked List	middle-of-the-linked-list	middle-of-the-linked-list	Easy
*3. Longest Substring Without Repeating Characters		longest-substring-without-repeating-characters	Medium
24. Swap Nodes in Pairs		swap-nodes-in-pairs	Medium
413. Arithmetic Slices		arithmetic-slices	Medium
(merge sort)21. Merge Two Sorted Lists		merge-two-sorted-lists	Easy
(fast&slow)141. Linked List Cycle		linked-list-cycle	Easy
946. Validate Stack Sequences		validate-stack-sequences	Medium
1721. Swapping Nodes in a Linked List		swapping-nodes-in-a-linked-list	Medium
11. Container With Most Water		container-with-most-water	Medium
923. 3Sum With Multiplicity		3sum-with-multiplicity	Medium
160. Intersection of Two Linked Lists		intersection-of-two-linked-lists	Easy
88. Merge Sorted Array		merge-sorted-array	Easy
1332. Remove Palindromic Subsequences		remove-palindromic-subsequences	Easy
167. Two Sum II - Input Array Is Sorted		two-sum-ii-input-array-is-sorted	Medium
1658. Minimum Operations to Reduce X to Zero		minimum-operations-to-reduce-x-to-zero	Medium
92. Reverse Linked List II		reverse-linked-list-ii	Medium
19. Remove Nth Node From End of List		remove-nth-node-from-end-of-list	Medium
(more than 2)16. 3Sum Closest		3sum-closest	Medium
2095. Delete the Middle Node of a Linked List		delete-the-middle-node-of-a-linked-list	Medium
76. Minimum Window Substring		minimum-window-substring	Hard
151. Reverse Words in a String	reverse-words-in-a-string	reverse-words-in-a-string	Medium

3 Simulation(not from ACwing

leetcode题目	Python代码	C++代码	难度
54. Spiral Matrix	spiral-matrix		Medium
1275. Find Winner on a Tic Tac Toe Game	find-winner-on-a-tic-tac-toe-game		Easy
1041. Robot Bounded In Circle		robot-bounded-in-circle	Medium
59. Spiral Matrix II		spiral-matrix-ii	Medium
622. Design Circular Queue		design-circular-queue	Medium

4 Binary Search(Not that simple)

leetcode题目	Python代码	C++代码	难度
154. Find Minimum in Rotated Sorted Array II	find-minimum-in-rotated-sorted-array-ii		Hard
668. Kth Smallest Number in Multiplication Table	kth-smallest-number-in-multiplication-table		Hard
540. Single Element in a Sorted Array	single-element-in-a-sorted-array	single-element-in-a-sorted-array	Medium
(binary search+matrix prefix sum)221. Maximal Square	maximal-square		Medium
410. Split Array Largest Sum		split-array-largest-sum	Hard
354. Russian Doll Envelopes		russian-doll-envelopes	Hard
1235. Maximum Profit in Job Scheduling		maximum-profit-in-job-scheduling	Hard
1539. Kth Missing Positive Number		kth-missing-positive-number	Easy

5 High Precision

leetcode题目	Python代码	C++代码	难度
43. Multiply Strings	multiply-strings		Medium

6 Bit Operation

leetcode题目	Python代码	C++代码	难度
461. Hamming Distance	hamming-distance		Easy
67. Add Binary		add-binary	Easy
136. Single Number		single-number	Easy
338. Counting Bits		counting-bits	Easy
318. Maximum Product of Word Lengths		maximum-product-of-word-lengths	Medium

7 Intervals Merge

leetcode题目	Python代码	C++代码	难度
986. Interval List Intersections	interval-list-intersections		Medium
56. Merge Intervals	merge-intervals		Medium
352. Data Stream as Disjoint Intervals		data-stream-as-disjoint-intervals	Medium

8 Prefix Sum

leetcode题目	Python代码	C++代码	难度
304. Range Sum Query 2D - Immutable		range-sum-query-2d-immutable	Medium
1695. Maximum Erasure Value		maximum-erasure-value	Medium
(kadane)363. Max Sum of Rectangle No Larger Than K		max-sum-of-rectangle-no-larger-than-k	Hard

Ⅱ Data Structure

1 Heap

leetcode题目	Python代码	C++代码	难度
1305. All Elements in Two Binary Search Trees		all-elements-in-two-binary-search-trees	Medium
23. Merge k Sorted Lists		merge-k-sorted-lists	Hard
1675. Minimize Deviation in Array		minimize-deviation-in-array	Hard
703. Kth Largest Element in a Stream		kth-largest-element-in-a-stream	Easy
(sort pairs)347. Top K Frequent Elements		top-k-frequent-elements	Medium
630. Course Schedule III		course-schedule-iii	Hard
1696. Jump Game VI		jump-game-vi	Medium
378. Kth Smallest Element in a Sorted Matrix		kth-smallest-element-in-a-sorted-matrix	Medium
1338. Reduce Array Size to The Half		reduce-array-size-to-the-half	Medium
1383. Maximum Performance of a Team		maximum-performance-of-a-team	Hard
295. Find Median from Data Stream		find-median-from-data-stream	Hard
1962. Remove Stones to Minimize the Total		remove-stones-to-minimize-the-total	Medium
1834. Single-Threaded CPU		single-threaded-cpu	Medium

2 Stack

leetcode题目	Python代码	C++代码	难度
(double stack)224. Basic Calculator	basic-calculator	basic-calculator	Hard
155. Min Stack	min-stack		Easy
(Monotonic Stack)739. Daily Temperatures	daily-temperatures	daily-temperatures	Medium
(monotonic stack)85. Maximal Rectangle	maximal-rectangle		Hard
(double Stack)394. Decode String	decode-string		Medium
(double Stack)227. Basic Calculator II	basic-calculator-ii		Medium
(monotonic stack)84. Largest Rectangle in Histogram		largest-rectangle-in-histogram	Hard
(Monotonic Stack)402. Remove K Digits		remove-k-digits	Medium
20. Valid Parentheses		valid-parentheses	Easy
1249. Minimum Remove to Make Valid Parentheses		minimum-remove-to-make-valid-parentheses	Medium
856. Score of Parentheses		score-of-parentheses	Medium
316. Remove Duplicate Letters		remove-duplicate-letters	Medium
1209. Remove All Adjacent Duplicates in String II		remove-all-adjacent-duplicates-in-string-ii	Medium
456. 132 Pattern		132-pattern	Medium
32. Longest Valid Parentheses		longest-valid-parentheses	Hard
(mono)901. Online Stock Span		online-stock-span	Medium
1047. Remove All Adjacent Duplicates In String		remove-all-adjacent-duplicates-in-string	Easy
(mono)907. Sum of Subarray Minimums		sum-of-subarray-minimums	Medium
232. Implement Queue using Stacks		implement-queue-using-stacks	Easy
150. Evaluate Reverse Polish Notation		evaluate-reverse-polish-notation	Medium

3 Heap Optimization

|502. IPO||ipo|Hard

4 Hash Table

leetcode题目	Python代码	C++代码	难度
1189. Maximum Number of Balloons	maximum-number-of-balloons		Easy
350. Intersection of Two Arrays II	intersection-of-two-arrays-ii		Easy
442. Find All Duplicates in an Array	find-all-duplicates-in-an-array		Medium
(binary_search+hash)1044. Longest Duplicate Substring	longest-duplicate-substring		Hard
973. K Closest Points to Origin	k-closest-points-to-origin		Medium
1010. Pairs of Songs With Total Durations Divisible by 60	pairs-of-songs-with-total-durations-divisible-by-60		Medium
290. Word Pattern		word-pattern	Easy
142. Linked List Cycle II		linked-list-cycle-ii	Medium
454. 4Sum II		4sum-ii	Medium
525. Contiguous Array		contiguous-array	Medium
389. Find the Difference		find-the-difference	Easy
532. K-diff Pairs in an Array		k-diff-pairs-in-an-array	Medium
560. Subarray Sum Equals K		subarray-sum-equals-k	Medium
567. Permutation in String		permutation-in-string	Medium
1288. Remove Covered Intervals		remove-covered-intervals	Medium
169. Majority Element		majority-element	Easy
895. Maximum Frequency Stack		maximum-frequency-stack	Hard
(open addressing)705. Design HashSet		design-hashset	Easy
(open addressing)706. Design HashMap		design-hashmap	Easy
1396. Design Underground System		design-underground-system	Medium
1679. Max Number of K-Sum Pairs		max-number-of-k-sum-pairs	Medium
47. Permutations II		permutations-ii	Medium
745. Prefix and Suffix Search		prefix-and-suffix-search	Hard
1268. Search Suggestions System		search-suggestions-system	Medium
820. Short Encoding of Words		short-encoding-of-words	Medium
128. Longest Consecutive Sequence		longest-consecutive-sequence	Medium
1074. Number of Submatrices That Sum to Target		number-of-submatrices-that-sum-to-target	Hard
792. Number of Matching Subsequences		number-of-matching-subsequences	Medium
30. Substring with Concatenation of All Words		substring-with-concatenation-of-all-words	Hard
13. Roman to Integer		roman-to-integer	Easy
804. Unique Morse Code Words		unique-morse-code-words	Easy
659. Split Array into Consecutive Subsequences		split-array-into-consecutive-subsequences	Medium
336. Palindrome Pairs		palindrome-pairs	Hard
(split-string)609. Find Duplicate File in System		find-duplicate-file-in-system	Medium
218. The Skyline Problem		the-skyline-problem	Hard
981. Time Based Key-Value Store		time-based-key-value-store	Medium
(ordered map for presum)732. My Calendar III		my-calendar-iii	Hard
1832. Check if the Sentence Is Pangram		check-if-the-sentence-is-pangram	Easy
692. Top K Frequent Words		top-k-frequent-words	Medium
49. Group Anagrams		group-anagrams	Medium
2131. Longest Palindrome by Concatenating Two Letter Words		longest-palindrome-by-concatenating-two-letter-words	Medium
2225. Find Players With Zero or One Losses		find-players-with-zero-or-one-losses	Medium
1207. Unique Number of Occurrences		unique-number-of-occurrences	Easy
472. Concatenated Words		concatenated-words	Hard
460. LFU Cache		lfu-cache	Hard
904. Fruit Into Baskets		fruit-into-baskets	Medium
2306. Naming a Company		naming-a-company	Hard
2405. Optimal Partition of String		optimal-partition-of-string	Medium

5 Trie

leetcode题目	Python代码	C++代码	难度
208. Implement Trie (Prefix Tree)	implement-trie-prefix-tree	implement-trie-prefix-tree	Medium
212. Word Search II	word-search-ii	word-search-ii	Hard
1178. Number of Valid Words for Each Puzzle	number-of-valid-words-for-each-puzzle		Hard
1032. Stream of Characters	stream-of-characters		Hard
(trie of c++ version)211. Design Add and Search Words Data Structure		design-add-and-search-words-data-structure	Medium

6 Disjoint Set Union

leetcode题目	Python代码	C++代码	难度
952. Largest Component Size by Common Factor	largest-component-size-by-common-factor		Hard
(DSUorDFS)200. Number of Islands	number-of-islands	number-of-islands	Medium
721. Accounts Merge	accounts-merge		Medium
1202. Smallest String With Swaps		smallest-string-with-swaps	Medium
990. Satisfiability of Equality Equations		satisfiability-of-equality-equations	Medium
1971. Find if Path Exists in Graph		find-if-path-exists-in-graph	Medium
1061. Lexicographically Smallest Equivalent String		lexicographically-smallest-equivalent-string	Medium
2421. Number of Good Paths		number-of-good-paths	Hard

Ⅲ Search and Graph theory

1 DFS

leetcode题目	Python代码	C++代码	难度
282. Expression Add Operators	expression-add-operators		Hard
(DFSorDP)1239. Maximum Length of a Concatenated String with Unique Characters	maximum-length-of-a-concatenated-string-with-unique-characters	maximum-length-of-a-concatenated-string-with-unique-characters	Medium
698. Partition to K Equal Sum Subsets	partition-to-k-equal-sum-subsets		Medium
79. Word Search	word-search	word-search	Medium
994. Rotting Oranges	rotting-oranges		Medium
430. Flatten a Multilevel Doubly Linked List	flatten-a-multilevel-doubly-linked-list		Medium
130. Surrounded Regions	surrounded-regions		Medium
980. Unique Paths III	unique-paths-iii	unique-paths-iii	Hard
129. Sum Root to Leaf Numbers	sum-root-to-leaf-numbers	sum-root-to-leaf-numbers	Medium
797. All Paths From Source to Target	all-paths-from-source-to-target	all-paths-from-source-to-target	Medium
(extreme small dfs)337. House Robber III	house-robber-iii		Medium
563. Binary Tree Tilt	binary-tree-tilt		Easy
1306. Jump Game III	jump-game-iii		Medium
(DPorDFS+memorization)416. Partition Equal Subset Sum	partition-equal-subset-sum		Medium
938. Range Sum of BST	range-sum-of-bst	range-sum-of-bst	Easy
1026. Maximum Difference Between Node and Ancestor	maximum-difference-between-node-and-ancestor	maximum-difference-between-node-and-ancestor	Medium
131. Palindrome Partitioning		palindrome-partitioning	Medium
1463. Cherry Pickup II		cherry-pickup-ii	Hard
1022. Sum of Root To Leaf Binary Numbers		sum-of-root-to-leaf-binary-numbers	Easy
1510. Stone Game IV		stone-game-iv	Hard
78. Subsets		subsets	Medium
104. Maximum Depth of Binary Tree		maximum-depth-of-binary-tree	Easy
39. Combination Sum		combination-sum	Medium
133. Clone Graph		clone-graph	Medium
538. Convert BST to Greater Tree		convert-bst-to-greater-tree	Medium
897. Increasing Order Search Tree		increasing-order-search-tree	Easy
230. Kth Smallest Element in a BST		kth-smallest-element-in-a-bst	Medium
(inorder)99. Recover Binary Search Tree		recover-binary-search-tree	Medium
(inorder)173. Binary Search Tree Iterator		binary-search-tree-iterator	Medium
341. Flatten Nested List Iterator		flatten-nested-list-iterator	Medium
216. Combination Sum III		combination-sum-iii	Medium
1379. Find a Corresponding Node of a Binary Tree in a Clone of That Tree		find-a-corresponding-node-of-a-binary-tree-in-a-clone-of-that-tree	Medium
329. Longest Increasing Path in a Matrix		longest-increasing-path-in-a-matrix	Hard
51. N-Queens		n-queens	Hard
52. N-Queens II		n-queens-ii	Hard
968. Binary Tree Cameras		binary-tree-cameras	Hard
509. Fibonacci Number		fibonacci-number	Easy
473. Matchsticks to Square		matchsticks-to-square	Medium
105. Construct Binary Tree from Preorder and Inorder Traversal		construct-binary-tree-from-preorder-and-inorder-traversal	Medium
695. Max Area of Island		max-area-of-island	Medium
240. Search a 2D Matrix II		search-a-2d-matrix-ii	Medium
236. Lowest Common Ancestor of a Binary Tree		lowest-common-ancestor-of-a-binary-tree	Medium
114. Flatten Binary Tree to Linked List		flatten-binary-tree-to-linked-list	Medium
108. Convert Sorted Array to Binary Search Tree		convert-sorted-array-to-binary-search-tree	Easy
98. Validate Binary Search Tree		validate-binary-search-tree	Medium
235. Lowest Common Ancestor of a Binary Search Tree		lowest-common-ancestor-of-a-binary-search-tree	Easy
417. Pacific Atlantic Water Flow		pacific-atlantic-water-flow	Medium
1448. Count Good Nodes in Binary Tree		count-good-nodes-in-binary-tree	Medium
967. Numbers With Same Consecutive Differences		numbers-with-same-consecutive-differences	Medium
987. Vertical Order Traversal of a Binary Tree		vertical-order-traversal-of-a-binary-tree	Hard
814. Binary Tree Pruning		binary-tree-pruning	Medium
606. Construct String from Binary Tree		construct-string-from-binary-tree	Easy
94. Binary Tree Inorder Traversal		binary-tree-inorder-traversal	Easy
113. Path Sum II		path-sum-ii	Medium
112. Path Sum		path-sum	Easy
623. Add One Row to Tree		add-one-row-to-tree	Medium
653. Two Sum IV - Input is a BST		two-sum-iv-input-is-a-bst	Easy
38. Count and Say		count-and-say	Medium
1706. Where Will the Ball Fall		where-will-the-ball-fall	Medium
947. Most Stones Removed with Same Row or Column		most-stones-removed-with-same-row-or-column	Medium
872. Leaf-Similar Trees		leaf-similar-trees	Easy
1339. Maximum Product of Splitted Binary Tree		maximum-product-of-splitted-binary-tree	Medium
124. Binary Tree Maximum Path Sum		binary-tree-maximum-path-sum	Hard
834. Sum of Distances in Tree		sum-of-distances-in-tree	Hard
144. Binary Tree Preorder Traversal		binary-tree-preorder-traversal	Easy
100. Same Tree		same-tree	Easy
1443. Minimum Time to Collect All Apples in a Tree		minimum-time-to-collect-all-apples-in-a-tree	Medium
1519. Number of Nodes in the Sub-Tree With the Same Label		number-of-nodes-in-the-sub-tree-with-the-same-label	Medium
2246. Longest Path With Different Adjacent Characters		longest-path-with-different-adjacent-characters	Hard
491. Non-decreasing Subsequences		non-decreasing-subsequences	Medium
93. Restore IP Addresses		restore-ip-addresses	Medium
2359. Find Closest Node to Given Two Nodes		find-closest-node-to-given-two-nodes	Medium
2477. Minimum Fuel Cost to Report to the Capital		minimum-fuel-cost-to-report-to-the-capital	Medium
783. Minimum Distance Between BST Nodes		minimum-distance-between-bst-nodes	Easy
427. Construct Quad Tree		construct-quad-tree	Medium
652. Find Duplicate Subtrees		find-duplicate-subtrees	Medium
109. Convert Sorted List to Binary Search Tree		convert-sorted-list-to-binary-search-tree	Medium
101. Symmetric Tree		symmetric-tree	Easy
1319. Number of Operations to Make Network Connected		number-of-operations-to-make-network-connected	Medium
2316. Count Unreachable Pairs of Nodes in an Undirected Graph		count-unreachable-pairs-of-nodes-in-an-undirected-graph	Medium
87. Scramble String		scramble-string	Hard
1254. Number of Closed Islands		number-of-closed-islands	Medium
1020. Number of Enclaves		number-of-enclaves	Medium

2 BFS

leetcode题目	Python代码	C++代码	难度
1293. Shortest Path in a Grid with Obstacles Elimination	shortest-path-in-a-grid-with-obstacles-elimination	shortest-path-in-a-grid-with-obstacles-elimination	Hard
310. Minimum Height Trees	minimum-height-trees		Medium
116. Populating Next Right Pointers in Each Node	populating-next-right-pointers-in-each-node		Medium
1345. Jump Game IV		jump-game-iv	Hard
127. Word Ladder		word-ladder	Hard
847. Shortest Path Visiting All Nodes		shortest-path-visiting-all-nodes	Hard
662. Maximum Width of Binary Tree		maximum-width-of-binary-tree	Medium
1631. Path With Minimum Effort		path-with-minimum-effort	Medium
117. Populating Next Right Pointers in Each Node II		populating-next-right-pointers-in-each-node-ii	Medium
1302. Deepest Leaves Sum		deepest-leaves-sum	Medium
1091. Shortest Path in Binary Matrix		shortest-path-in-binary-matrix	Medium
199. Binary Tree Right Side View		binary-tree-right-side-view	Medium
102. Binary Tree Level Order Traversal		binary-tree-level-order-traversal	Medium
126. Word Ladder II		word-ladder-ii	Hard
637. Average of Levels in Binary Tree		average-of-levels-in-binary-tree	Easy
429. N-ary Tree Level Order Traversal		n-ary-tree-level-order-traversal	Medium
433. Minimum Genetic Mutation		minimum-genetic-mutation	Medium
1926. Nearest Exit from Entrance in Maze		nearest-exit-from-entrance-in-maze	Medium
909. Snakes and Ladders		snakes-and-ladders	Medium
787. Cheapest Flights Within K Stops		cheapest-flights-within-k-stops	Medium
1162. As Far from Land as Possible		as-far-from-land-as-possible	Medium
1129. Shortest Path with Alternating Colors		shortest-path-with-alternating-colors	Medium
103. Binary Tree Zigzag Level Order Traversal		binary-tree-zigzag-level-order-traversal	Medium
2492. Minimum Score of a Path Between Two Cities		minimum-score-of-a-path-between-two-cities	Medium

3 Topological Sorting

leetcode题目	Python代码	C++代码	难度
210. Course Schedule II	course-schedule-ii		Medium

4 Shortest Path

leetcode题目	Python代码	C++代码	难度
(Dijkstra or any other)882. Reachable Nodes In Subdivided Graph	reachable-nodes-in-subdivided-graph		Hard
(Dijkstra)743. Network Delay Time		network-delay-time	Medium

5 Minimum Spanning Tree

leetcode题目	Python代码	C++代码	难度
1584. Min Cost to Connect All Points		min-cost-to-connect-all-points	Medium

6 Bipartite Graph

leetcode题目	Python代码	C++代码	难度
785. Is Graph Bipartite?		is-graph-bipartite	Medium
886. Possible Bipartition		possible-bipartition	Medium

Ⅳ Mathematics

Ⅴ Dynamic Programming

1 Linear DP

leetcode题目	Python代码	C++代码	难度
(like preprocessing)764. Largest Plus Sign	largest-plus-sign		Medium
1143. Longest Common Subsequence	longest-common-subsequence	longest-common-subsequence	Medium
(DFSorDP)174. Dungeon Game	dungeon-game		Hard
(DFSorDP)70. Climbing Stairs	climbing-stairs	climbing-stairs	Easy
123. Best Time to Buy and Sell Stock III	best-time-to-buy-and-sell-stock-iii		Hard
96. Unique Binary Search Trees	unique-binary-search-trees		Medium
122. Best Time to Buy and Sell Stock II	best-time-to-buy-and-sell-stock-ii		Medium
198. House Robber	house-robber	house-robber	Medium
152. Maximum Product Subarray	maximum-product-subarray		Medium
(hard)790. Domino and Tromino Tiling	domino-and-tromino-tiling	domino-and-tromino-tiling	Medium
121. Best Time to Buy and Sell Stock		best-time-to-buy-and-sell-stock	Easy
799. Champagne Tower		champagne-tower	Medium
(0/1-knapsack)740. Delete and Earn		delete-and-earn	Medium
63. Unique Paths II		unique-paths-ii	Easy
322. Coin Change		coin-change	Medium
474. Ones and Zeroes		ones-and-zeroes	Medium
120. Triangle		triangle	Medium
583. Delete Operation for Two Strings		delete-operation-for-two-strings	Medium
1048. Longest String Chain		longest-string-chain	Medium
97. Interleaving String		interleaving-string	Medium
746. Min Cost Climbing Stairs		min-cost-climbing-stairs	Easy
629. K Inverse Pairs Array		k-inverse-pairs-array	Hard
377. Combination Sum IV		combination-sum-iv	Medium
1220. Count Vowels Permutation		count-vowels-permutation	Hard
300. Longest Increasing Subsequence		longest-increasing-subsequence	Medium
823. Binary Trees With Factors		binary-trees-with-factors	Medium
871. Minimum Number of Refueling Stops		minimum-number-of-refueling-stops	Hard
188. Best Time to Buy and Sell Stock IV		best-time-to-buy-and-sell-stock-iv	Hard
91. Decode Ways		decode-ways	Medium
1155. Number of Dice Rolls With Target Sum		number-of-dice-rolls-with-target-sum	Medium
931. Minimum Falling Path Sum		minimum-falling-path-sum	Medium
926. Flip String to Monotone Increasing		flip-string-to-monotone-increasing	Medium
1626. Best Team With No Conflicts		best-team-with-no-conflicts	Medium
45. Jump Game II		jump-game-ii	Medium
72. Edit Distance		edit-distance	Hard
983. Minimum Cost For Tickets		minimum-cost-for-tickets	Medium
2218. Maximum Value of K Coins From Piles		maximum-value-of-k-coins-from-piles	Hard

2 Interval DP

leetcode题目	Python代码	C++代码	难度
5. Longest Palindromic Substring		longest-palindromic-substring	Medium

3 Counting Problem DP

leetcode题目	Python代码	C++代码	难度
446. Arithmetic Slices II - Subsequence	arithmetic-slices-ii-subsequence	arithmetic-slices-ii-subsequence	Hard
115. Distinct Subsequences	distinct-subsequences		Hard
279. Perfect Squares	perfect-squares	perfect-squares	Medium
309. Best Time to Buy and Sell Stock with Cooldown	best-time-to-buy-and-sell-stock-with-cooldown	best-time-to-buy-and-sell-stock-with-cooldown	Medium
368. Largest Divisible Subset	largest-divisible-subset		Medium
*62. Unique Paths	unique-paths		Medium

4 Digital Statistics DP(not precise probably

leetcode题目	Python代码	C++代码	难度
902. Numbers At Most N Given Digit Set	numbers-at-most-n-given-digit-set		Hard
1291. Sequential Digits		sequential-digits	Medium

5 State Compression DP

6 Memory Search

leetcode题目	Python代码	C++代码	难度
437. Path Sum III	path-sum-iii		Medium
312. Burst Balloons	burst-balloons		Hard
1359. Count All Valid Pickup and Delivery Options		count-all-valid-pickup-and-delivery-options	Hard
1473. Paint House III		paint-house-iii	Hard
576. Out of Boundary Paths		out-of-boundary-paths	Medium
1770. Maximum Score from Performing Multiplication Operations		maximum-score-from-performing-multiplication-operations	Medium
1335. Minimum Difficulty of a Job Schedule		minimum-difficulty-of-a-job-schedule	Hard

Ⅵ Greedy Algorithm

leetcode题目	Python代码	C++代码	难度
452. Minimum Number of Arrows to Burst Balloons		minimum-number-of-arrows-to-burst-balloons	Medium
881. Boats to Save People		boats-to-save-people	Medium
1029. Two City Scheduling		two-city-scheduling	Medium
1046. Last Stone Weight		last-stone-weight	Easy
1642. Furthest Building You Can Reach		furthest-building-you-can-reach	Medium
1647. Minimum Deletions to Make Character Frequencies Unique		minimum-deletions-to-make-character-frequencies-unique	Medium
406. Queue Reconstruction by Height		queue-reconstruction-by-height	Medium
135. Candy		candy	Hard
936. Stamping The Sequence		stamping-the-sequence	Hard
1996. The Number of Weak Characters in the Game		the-number-of-weak-characters-in-the-game	Medium
948. Bag of Tokens		bag-of-tokens	Medium
2007. Find Original Array From Doubled Array		find-original-array-from-doubled-array	Medium
2136. Earliest Possible Day of Full Bloom		earliest-possible-day-of-full-bloom	Hard

Ⅶ No Classification

leetcode题目	Python代码	C++代码	难度
485. Max Consecutive Ones	max-consecutive-ones		Easy
1328. Break a Palindrome	break-a-palindrome	break-a-palindrome	Medium
929. Unique Email Addresses	unique-email-addresses		Easy
725. Split Linked List in Parts	split-linked-list-in-parts		Medium
496. Next Greater Element I	next-greater-element-i		Easy
380. Insert Delete GetRandom O(1)	insert-delete-getrandom-o1	insert-delete-getrandom-o1	Medium
226. Invert Binary Tree	invert-binary-tree	invert-binary-tree	Easy
15. 3Sum	3sum		Medium
1413. Minimum Value to Get Positive Step by Step Sum	minimum-value-to-get-positive-step-by-step-sum		Easy
203. Remove Linked List Elements	remove-linked-list-elements		Easy
1217. Minimum Cost to Move Chips to The Same Position	minimum-cost-to-move-chips-to-the-same-position		Easy
1290. Convert Binary Number in a Linked List to Integer	convert-binary-number-in-a-linked-list-to-integer		Easy
1446. Consecutive Characters	consecutive-characters		Easy
147. Insertion Sort List	insertion-sort-list		Medium
1200. Minimum Absolute Difference	minimum-absolute-difference		Easy
143. Reorder List	reorder-list		Medium
476. Number Complement	number-complement		Easy
1009. Complement of Base 10 Integer	complement-of-base-10-integer		Easy
849. Maximize Distance to Closest Person		maximize-distance-to-closest-person	Medium
605. Can Place Flowers		can-place-flowers	Easy
134. Gas Station		gas-station	Medium
520. Detect Capital		detect-capital	Easy
941. Valid Mountain Array		valid-mountain-array	Easy
189. Rotate Array		rotate-array	Medium
1672. Richest Customer Wealth		richest-customer-wealth	Easy
438. Find All Anagrams in a String		find-all-anagrams-in-a-string	Medium
80. Remove Duplicates from Sorted Array II		remove-duplicates-from-sorted-array-ii	Medium
258. Add Digits		add-digits	Easy
171. Excel Sheet Column Number		excel-sheet-column-number	Easy
165. Compare Version Numbers		compare-version-numbers	Medium
228. Summary Ranges		summary-ranges	Easy
392. Is Subsequence		is-subsequence	Easy
82. Remove Duplicates from Sorted List II		remove-duplicates-from-sorted-list-ii	Medium
2. Add Two Numbers		add-two-numbers	Medium
61. Rotate List		rotate-list	Medium
138. Copy List with Random Pointer		copy-list-with-random-pointer	Medium
71. Simplify Path		simplify-path	Medium
1007. Minimum Domino Rotations For Equal Row		minimum-domino-rotations-for-equal-row	Medium
763. Partition Labels		partition-labels	Medium
1663. Smallest String With A Given Numeric Value		smallest-string-with-a-given-numeric-value	Medium
991. Broken Calculator		broken-calculator	Medium
1337. The K Weakest Rows in a Matrix		the-k-weakest-rows-in-a-matrix	Easy
287. Find the Duplicate Number		find-the-duplicate-number	Medium
344. Reverse String		reverse-string	Easy
680. Valid Palindrome II		valid-palindrome-ii	Easy
682. Baseball Game		baseball-game	Easy
1260. Shift 2D Grid		shift-2d-grid	Easy
289. Game of Life		game-of-life	Medium
700. Search in a Binary Search Tree		search-in-a-binary-search-tree	Easy
535. Encode and Decode TinyURL		encode-and-decode-tinyurl	Medium
284. Peeking Iterator		peeking-iterator	Medium
399. Evaluate Division		evaluate-division	Medium
844. Backspace String Compare		backspace-string-compare	Easy
905. Sort Array By Parity		sort-array-by-parity	Easy
225. Implement Stack using Queues		implement-stack-using-queues	Easy
17. Letter Combinations of a Phone Number		letter-combinations-of-a-phone-number	Medium
1641. Count Sorted Vowel Strings		count-sorted-vowel-strings	Medium
647. Palindromic Substrings		palindromic-substrings	Medium
191. Number of 1 Bits		number-of-1-bits	Easy
1342. Number of Steps to Reduce a Number to Zero		number-of-steps-to-reduce-a-number-to-zero	Easy
1461. Check If a String Contains All Binary Codes of Size K		check-if-a-string-contains-all-binary-codes-of-size-k	Medium
1480. Running Sum of 1d Array		running-sum-of-1d-array	Easy
1689. Partitioning Into Minimum Number Of Deci-Binary Numbers		partitioning-into-minimum-number-of-deci-binary-numbers	Medium
118. Pascal's Triangle		pascals-triangle	Easy
86. Partition List		partition-list	Medium
242. Valid Anagram		valid-anagram	Easy
890. Find and Replace Pattern		find-and-replace-pattern	Medium
916. Word Subsets		word-subsets	Medium
307. Range Sum Query - Mutable		range-sum-query-mutable	Medium
729. My Calendar I		my-calendar-i	Medium
387. First Unique Character in a String		first-unique-character-in-a-string	Easy
234. Palindrome Linked List		palindrome-linked-list	Easy
383. Ransom Note		ransom-note	Easy
869. Reordered Power of 2		reordered-power-of-2	Medium
1329. Sort the Matrix Diagonally		sort-the-matrix-diagonally	Medium
393. UTF-8 Validation		utf-8-validation	Medium
718. Maximum Length of Repeated Subarray		maximum-length-of-repeated-subarray	Medium
985. Sum of Even Numbers After Queries		sum-of-even-numbers-after-queries	Medium
557. Reverse Words in a String III		reverse-words-in-a-string-iii	Medium
838. Push Dominoes		push-dominoes	Medium
658. Find K Closest Elements		find-k-closest-elements	Medium
1578. Minimum Time to Make Rope Colorful		minimum-time-to-make-rope-colorful	Medium
334. Increasing Triplet Subsequence		increasing-triplet-subsequence	Medium
976. Largest Perimeter Triangle		largest-perimeter-triangle	Easy
237. Delete Node in a Linked List		delete-node-in-a-linked-list	Medium
219. Contains Duplicate II		contains-duplicate-ii	Easy
1662. Check If Two String Arrays are Equivalent		check-if-two-string-arrays-are-equivalent	Easy
766. Toeplitz Matrix		toeplitz-matrix	Easy
345. Reverse Vowels of a String		reverse-vowels-of-a-string	Easy
1323. Maximum 69 Number		maximum-69-number	Easy
1544. Make The String Great		make-the-string-great	Easy
26. Remove Duplicates from Sorted Array		remove-duplicates-from-sorted-array	Easy
223. Rectangle Area		rectangle-area	Medium
36. Valid Sudoku		valid-sudoku	Medium
1704. Determine if String Halves Are Alike		determine-if-string-halves-are-alike	Easy
1657. Determine if Two Strings Are Close		determine-if-two-strings-are-close	Medium
2256. Minimum Average Difference		minimum-average-difference	Medium
2389. Longest Subsequence With Limited Sum		longest-subsequence-with-limited-sum	Easy
2279. Maximum Bags With Full Capacity of Rocks		maximum-bags-with-full-capacity-of-rocks	Medium
944. Delete Columns to Make Sorted		delete-columns-to-make-sorted	Easy
2244. Minimum Rounds to Complete All Tasks		minimum-rounds-to-complete-all-tasks	Medium
1833. Maximum Ice Cream Bars		maximum-ice-cream-bars	Medium
57. Insert Interval		insert-interval	Medium
918. Maximum Sum Circular Subarray		maximum-sum-circular-subarray	Medium
6. Zigzag Conversion		zigzag-conversion	Medium
1470. Shuffle the Array		shuffle-the-array	Easy
1523. Count Odd Numbers in an Interval Range		count-odd-numbers-in-an-interval-range	Easy
989. Add to Array-Form of Integer		add-to-array-form-of-integer	Easy
443. String Compression		string-compression	Medium
2444. Count Subarrays With Fixed Bounds		count-subarrays-with-fixed-bounds	Hard
1472. Design Browser History		design-browser-history	Medium
2348. Number of Zero-Filled Subarrays		number-of-zero-filled-subarrays	Medium
2360. Longest Cycle in a Graph		longest-cycle-in-a-graph	Hard

Ⅷ Math Property

leetcode题目	Python代码	C++代码	难度
782. Transform to Chessboard	transform-to-chessboard		Hard
463. Island Perimeter	island-perimeter		Easy
201. Bitwise AND of Numbers Range	bitwise-and-of-numbers-range		Medium
(heap_optim or math)260. Single Number III	single-number-iii		Medium
878. Nth Magical Number	nth-magical-number		Hard
1015. Smallest Integer Divisible by K	smallest-integer-divisible-by-k		Medium
(in&out degree)997. Find the Town Judge	find-the-town-judge	find-the-town-judge	Easy
382. Linked List Random Node		linked-list-random-node	Medium
421. Maximum XOR of Two Numbers in an Array		maximum-xor-of-two-numbers-in-an-array	Medium
31. Next Permutation		next-permutation	Medium
268. Missing Number		missing-number	Easy
29. Divide Two Integers		divide-two-integers	Medium
867. Transpose Matrix		transpose-matrix	Easy
1354. Construct Target Array With Multiple Sums		construct-target-array-with-multiple-sums	Hard
462. Minimum Moves to Equal Array Elements II		minimum-moves-to-equal-array-elements-ii	Medium
458. Poor Pigs		poor-pigs	Hard
342. Power of Four		power-of-four	Easy
326. Power of Three		power-of-three	Easy
48. Rotate Image		rotate-image	Medium
1457. Pseudo-Palindromic Paths in a Binary Tree		pseudo-palindromic-paths-in-a-binary-tree	Medium
42. Trapping Rain Water		trapping-rain-water	Hard
1680. Concatenation of Consecutive Binary Numbers		concatenation-of-consecutive-binary-numbers	Medium
12. Integer to Roman		integer-to-roman	Medium
523. Continuous Subarray Sum		continuous-subarray-sum	Medium
835. Image Overlap		image-overlap	Medium
899. Orderly Queue		orderly-queue	Hard
263. Ugly Number		ugly-number	Easy
587. Erect the Fence		erect-the-fence	Hard
149. Max Points on a Line		max-points-on-a-line	Hard
974. Subarray Sums Divisible by K		subarray-sums-divisible-by-k	Medium
1071. Greatest Common Divisor of Strings		greatest-common-divisor-of-strings	Easy
(KMP)28. Find the Index of the First Occurrence in a String		find-the-index-of-the-first-occurrence-in-a-string	Medium

Ⅸ Outsiders (never learned the algorithm)

leetcode题目	Python代码	C++代码	难度
(Tarjan)1192. Critical Connections in a Network		critical-connections-in-a-network	Hard