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DSA learning path

Trees & Graphs

BFS, DFS, recursion and topological order.

Start with Maximum Depth of a Binary Tree

Problems in this path

  1. Maximum Depth of a Binary Tree
    Easy · Depth-First Search
    Open
  2. Level Order Traversal
    Medium · Breadth-First Search
    Open
  3. Validate a Binary Search Tree
    Medium · Depth-First Search
    Open
  4. Number of Islands
    Medium · Grid DFS
    Open
  5. Course Schedule
    Medium · Topological Sort
    Open
  6. Shortest Paths with Dijkstra
    Medium · Dijkstra's Algorithm
    Open
  7. Minimum Cost to Connect a Graph
    Hard · Kruskal + Union-Find
    Open
  8. Binary Tree Inorder Traversal
    Easy · Iterative Tree Stack
    Open
  9. Binary Tree Diameter
    Medium · Postorder Heights
    Open
  10. Check Tree Height Balance
    Easy · Sentinel Postorder
    Open

Read first

Binary Trees and Traversals

Roots, children and leaves; the four ways to walk a tree (pre-, in-, post- and level-order); and how recursion makes tree code short.

15 min read

Binary Search Trees

A binary tree that keeps itself sorted. How search, insert and the three cases of delete work, and why balance decides whether it's O(log n) or O(n).

16 min read

Graphs, BFS and DFS

Vertices and edges, adjacency lists, and the two ways to explore a graph: breadth-first search for shortest paths and depth-first search for everything else.

17 min read

Weighted Graphs, Dijkstra and Union–Find

Extend BFS to weighted shortest paths, connect a graph at minimum cost, and maintain changing components with union–find.

21 min read