Bird
Raised Fist0

Given a binary tree, you want to list all root-to-leaf paths where the sum of node values matches a given target. Which technique is most appropriate to systematically explore all such paths?

easy💻 Programming Q1 of Q15
Tree: Depth-First Search - Path Sum II (All Root-to-Leaf Paths)
Given a binary tree, you want to list all root-to-leaf paths where the sum of node values matches a given target. Which technique is most appropriate to systematically explore all such paths?
ADepth-first search with backtracking
BBreadth-first search with level order traversal
CBinary search on node values
DDynamic programming with memoization
Step-by-Step Solution
Solution:

  1. Step 1: Choose traversal method for root-to-leaf path enumeration

    To find all root-to-leaf paths, DFS is suitable because it explores each path fully before backtracking.

  2. Step 2: Use backtracking to explore and revert paths

    Backtracking allows us to explore a path, check sums, and revert changes to explore other paths.

  3. Final Answer:

    Option A → Option A

  4. Quick Check:

    DFS explores all paths exhaustively [OK]
Quick Trick: DFS with backtracking explores all root-to-leaf paths [OK]
Common Mistakes:
MISTAKES
  • Choosing BFS which doesn't naturally track root-to-leaf paths
  • Using binary search which is irrelevant for tree path sums
  • Applying DP without overlapping subproblems
Trap Explanation:
PITFALL
  • BFS and DP seem plausible but don't naturally enumerate all root-to-leaf paths
Interviewer Note:
CONTEXT
  • Tests understanding of appropriate traversal and backtracking for path enumeration
Master "Path Sum II (All Root-to-Leaf Paths)" in Tree: Depth-First Search

3 interactive learning modes - each teaches the same concept differently

Try ItSolutionTrace

Want More Practice?

15+ quiz questions · All difficulty levels · Free

Free Signup - Practice All Questions
More Tree: Depth-First Search Quizzes
Binary Tree Inorder Traversal - Binary Tree Inorder Traversal - Quiz 8hard Binary Tree Maximum Path Sum - Binary Tree Maximum Path Sum - Quiz 8hard Binary Tree Maximum Path Sum - Binary Tree Maximum Path Sum - Quiz 15hard Construct Tree from Inorder and Postorder - Construct Tree from Inorder and Postorder - Quiz 13medium Count Complete Tree Nodes - Count Complete Tree Nodes - Quiz 10hard Flatten Binary Tree to Linked List - Flatten Binary Tree to Linked List - Quiz 11easy Invert Binary Tree - Invert Binary Tree - Quiz 5medium Invert Binary Tree - Invert Binary Tree - Quiz 14medium Serialize and Deserialize Binary Tree - Serialize and Deserialize Binary Tree - Quiz 5medium Symmetric Tree (DFS Approach) - Symmetric Tree (DFS Approach) - Quiz 9hard