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Problems

208 problems

Has videoPremium onlyReset
Array1,212Hash Table473String437Math331Greedy330Dynamic Programming327Sorting302Depth-First Search208Binary Search189Breadth-First Search166Matrix163Tree158Prefix Sum155Two Pointers150Database137All topics

Medium · 208 results

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TitleSolutionAcceptDifficultyTopics
98. Validate Binary Search TreeVideo
Solution36.1%Medium
Binary Search Tree, Binary Tree +2· 18 companies
99. Recover Binary Search TreeVideo
Solution60.9%Medium
Binary Search Tree, Binary Tree +2· 8 companies
113. Path Sum IIVideo
Solution62.6%Medium
Backtracking, Binary Tree +2· 10 companies
114. Flatten Binary Tree to Linked ListVideo
Solution71.6%Medium
Binary Tree, Depth-First Search +3· 8 companies
116. Populating Next Right Pointers in Each NodeVideo
Solution67.6%Medium
Binary Tree, Breadth-First Search +3· 8 companies
117. Populating Next Right Pointers in Each Node IIVideo
Solution57.9%Medium
Binary Tree, Breadth-First Search +3· 7 companies
129. Sum Root to Leaf NumbersVideo
Solution70.3%Medium
Binary Tree, Depth-First Search +1· 7 companies
130. Surrounded RegionsVideo
Solution46.1%Medium
Array, Breadth-First Search +3· 12 companies
133. Clone GraphVideo
Solution66.1%Medium
Breadth-First Search, Depth-First Search +2· 18 companies
156. Binary Tree Upside DownVideoPremium
Solution65.4%Medium
Binary Tree, Depth-First Search +1· 2 companies
199. Binary Tree Right Side ViewVideo
Solution71.5%Medium
Binary Tree, Breadth-First Search +2· 14 companies
200. Number of IslandsVideo
Solution65.2%Medium
Array, Breadth-First Search +3· 86 companies
207. Course ScheduleVideo
Solution52.2%Medium
Breadth-First Search, Depth-First Search +2· 45 companies
210. Course Schedule IIVideo
Solution56.3%Medium
Breadth-First Search, Depth-First Search +2· 36 companies
211. Design Add and Search Words Data StructureVideo
Solution48.9%Medium
Depth-First Search, Design +2· 13 companies
230. Kth Smallest Element in a BSTVideo
Solution77.2%Medium
Binary Search Tree, Binary Tree +2· 12 companies
235. Lowest Common Ancestor of a Binary Search TreeVideo
Solution71.4%Medium
Binary Search Tree, Binary Tree +2· 10 companies
236. Lowest Common Ancestor of a Binary TreeVideo
Solution70.1%Medium
Binary Tree, Depth-First Search +1· 22 companies
250. Count Univalue SubtreesVideoPremium
Solution57.5%Medium
Binary Tree, Depth-First Search +1· 4 companies
261. Graph Valid TreeVideoPremium
Solution49.9%Medium
Breadth-First Search, Depth-First Search +2· 9 companies
285. Inorder Successor in BSTVideoPremium
Solution51.2%Medium
Binary Search Tree, Binary Tree +2· 6 companies
298. Binary Tree Longest Consecutive SequenceVideoPremium
Solution54.7%Medium
Binary Tree, Depth-First Search +1· 4 companies
310. Minimum Height TreesVideo
Solution42.4%Medium
Breadth-First Search, Depth-First Search +2· 7 companies
314. Binary Tree Vertical Order TraversalVideoPremium
Solution57.8%Medium
Binary Tree, Breadth-First Search +4· 9 companies
323. Number of Connected Components in an Undirected GraphVideoPremium
Solution64.9%Medium
Breadth-First Search, Depth-First Search +2· 7 companies
333. Largest BST SubtreeVideoPremium
Solution45.8%Medium
Binary Search Tree, Binary Tree +3· 2 companies
337. House Robber IIIVideo
Solution56.3%Medium
Binary Tree, Depth-First Search +2· 13 companies
339. Nested List Weight SumVideoPremium
Solution85.9%Medium
Breadth-First Search, Depth-First Search· 6 companies
341. Flatten Nested List IteratorVideo
Solution65.6%Medium
Depth-First Search, Design +4· 19 companies
364. Nested List Weight Sum IIVideoPremium
Solution66.8%Medium
Breadth-First Search, Depth-First Search +1· 3 companies
365. Water and Jug ProblemVideo
Solution46.4%Medium
Breadth-First Search, Depth-First Search +1· 8 companies
366. Find Leaves of Binary TreeVideoPremium
Solution81.4%Medium
Binary Tree, Depth-First Search +1· 6 companies
385. Mini ParserVideo
Solution44.0%Medium
Depth-First Search, Stack +1· 4 companies
386. Lexicographical NumbersVideo
Solution76.2%Medium
Depth-First Search, Trie· 6 companies
388. Longest Absolute File PathVideo
Solution49.9%Medium
Depth-First Search, Stack +1· 4 companies
399. Evaluate DivisionVideo
Solution64.7%Medium
Array, Breadth-First Search +5· 23 companies
417. Pacific Atlantic Water FlowVideo
Solution61.3%Medium
Array, Breadth-First Search +2· 11 companies
419. Battleships in a BoardVideo
Solution77.4%Medium
Array, Depth-First Search +1· 8 companies
426. Convert Binary Search Tree to Sorted Doubly Linked ListVideoPremium
Solution65.2%Medium
Binary Search Tree, Binary Tree +5· 4 companies
430. Flatten a Multilevel Doubly Linked ListVideo
Solution63.3%Medium
Depth-First Search, Doubly-Linked List +1· 6 companies
437. Path Sum IIIVideo
Solution46.6%Medium
Binary Tree, Depth-First Search +1· 11 companies
449. Serialize and Deserialize BSTVideo
Solution60.1%Medium
Binary Search Tree, Binary Tree +5· 4 companies
490. The MazeVideoPremium
Solution60.4%Medium
Array, Breadth-First Search +2· 13 companies
505. The Maze IIVideoPremium
Solution55.0%Medium
Array, Breadth-First Search +5· 5 companies
508. Most Frequent Subtree SumVideo
Solution69.6%Medium
Binary Tree, Depth-First Search +2· 3 companies
513. Find Bottom Left Tree ValueVideo
Solution72.2%Medium
Binary Tree, Breadth-First Search +2· 7 companies
515. Find Largest Value in Each Tree RowVideo
Solution66.3%Medium
Binary Tree, Breadth-First Search +2· 8 companies
529. MinesweeperVideo
Solution68.7%Medium
Array, Breadth-First Search +2· 9 companies
536. Construct Binary Tree from StringVideoPremium
Solution58.7%Medium
Binary Tree, Depth-First Search +3· 3 companies
538. Convert BST to Greater TreeVideo
Solution72.1%Medium
Binary Search Tree, Binary Tree +2· 4 companies
Showing 1–50 of 208