DSA pattern
Tree Traversal
Tree traversals visit every node in a specific order. DFS explores depth-first (preorder, inorder, postorder), while BFS explores level-by-level. Inorder on BST gives sorted order.
When to use
5 signals- 01Processing all nodes in a tree
- 02BST operations (inorder = sorted)
- 03Level-order processing (BFS)
- 04Tree serialization/deserialization
- 05Finding paths or depths
In interviews, call out the pattern early. It helps interviewers follow your reasoning and keeps your implementation focused. After solving, explain tradeoffs in plain language: why this approach is efficient, where it can break, and what edge cases you would test first.
Practice problems
5 listed- 01Maximum DepthPractice →
- 02Same TreePractice →
- 03Invert Binary TreePractice →
- 04Level Order TraversalPractice →
- 05Validate BSTPractice →
Build a review loop
Treat each pattern as a repeating cycle, not a one-time read. Solve a fresh problem today, revisit the same pattern in 2-3 days, and run one timed attempt at the end of the week. This turns short-term familiarity into reliable recall for live interviews.
When reviewing, re-derive the core steps from scratch before checking a reference solution. If you can explain the state transitions and edge cases clearly, you are much more likely to execute well under interview pressure.