Lesson overview · Free interview practice

Tree DFS

Explore trees deeply using Depth-First Search.

Topics in the full lesson
  • Concept and Use Cases
  • When to Use
  • Time and Space Complexity
  • Types of DFS Traversal
  • Pre-Order Traversal
  • In-Order Traversal
  • Post-Order Traversal

Practice Problems

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Completion marks record your own progress, not an automatically checked result. The task type does not determine whether it is optional.

CodingEasy

Path Sum

Question

Given the root of a binary tree and an integer targetSum, return true if the tree has a root-to-leaf path whose node values add up exactly to targetSum.

Take a moment to think about this before revealing the answer

Explain your reasoning or try an implementation before comparing answers.

Practice on LeetCode
CodingMedium

Validate Binary Search Tree

Question

Determine whether a given binary search tree is valid, ensuring that all node values are within the correct range relative to its left and right subtrees.

Take a moment to think about this before revealing the answer

Explain your reasoning or try an implementation before comparing answers.

Practice on LeetCode
CodingHard

Maximum Path Sum

Question

Given the root of a binary tree, return the maximum path sum of any non-empty path. A path is any sequence of nodes connected by edges, where each pair of adjacent nodes shares an edge and any node appears at most once. The path does not need to pass through the root.

Take a moment to think about this before revealing the answer

Explain your reasoning or try an implementation before comparing answers.

Practice on LeetCode

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