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🌳 Interview Prep

Trees, Graphs & DP

Trees, heaps, tries, graphs, backtracking and dynamic programming: what separates a pass from a strong pass at big tech.

📘 Learn it from scratch

Visual, hands-on lessons for every pattern in this topic. Do the lesson, then come back and the questions click.

Trees & Binary Search TreesTree TraversalsBinary Search Trees in DepthHeaps & Priority QueuesTries (Prefix Trees)Graphs: BFS & DFSGrids & Matrix TraversalDynamic Programming, DemystifiedRecursion, Step by Step

100 questions, most asked first

Ordered so the most useful questions for learning each pattern come first.

Any difficulty Easy Medium Hard

All patterns Tree DFS Tree BFS BST Grid graph 1D DP Heap Graph BFS/DFS Topological sort Backtracking 2D DP Trie Union-find Shortest path Recursion

#1Maximum Depth of Binary TreeTree DFSEasyFree #2Invert Binary TreeTree DFSEasyFree #3Same TreeTree DFSEasyFree #8Climbing Stairs1D DPEasyFree Unlock 13 more Trees, Graphs & DP questions · all 1,200 questions for $39/year (about 11¢ a day)See full access #11Subtree of Another TreeTree DFSEasy🔒#12Diameter of Binary TreeTree DFSEasy🔒#13Balanced Binary TreeTree DFSEasy🔒#46Last Stone WeightHeapEasy🔒#62Min Cost Climbing Stairs1D DPEasy🔒#72Binary Tree Inorder Traversal (Iterative)Tree DFSEasy🔒#73Symmetric TreeTree DFSEasy🔒#74Path SumTree DFSEasy🔒#77Convert Sorted Array to Balanced BSTBSTEasy🔒#81Average of Levels in Binary TreeTree BFSEasy🔒#82Minimum Depth of Binary TreeTree BFSEasy🔒#88Find the Town JudgeGraph BFS/DFSEasy🔒#95Fibonacci Number (Recursion → Memo → DP)RecursionEasy🔒