Greedy on binary tree
Last updated: July 14, 2025
Quick Overview
Given a binary tree, implement a greedy algorithm to find the maximum sum of non-adjacent nodes. You need to return the maximum sum that can be obtained by selecting nodes such that no two selected nodes are direct parent-child pairs. The input will be the root node of the binary tree, and the output should be an integer representing the maximum sum.
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Given a binary tree, implement a greedy algorithm to find the maximum sum of non-adjacent nodes. You need to return the maximum sum that can be obtained by selecting nodes such that no two selected nodes are direct parent-child pairs. The input will be the root node of the binary tree, and the output should be an integer representing the maximum sum.
Coding interviews at LinkedIn focus on problem-solving approach as much as the final solution. The interviewer wants to see you break down the problem, consider edge cases, and optimize iteratively. Communication throughout the process is key.
What the Interviewer Expects
- Quickly identify the optimal approach and its theoretical basis
- Handle complex algorithm design with multiple interacting components
- Write concise, elegant code under time pressure
- Prove correctness of your approach and discuss alternative solutions
- Optimize beyond the obvious: discuss constant factor improvements
- Address follow-up variations and explain how the solution generalizes
Key Topics to Cover
How to Approach This
- Clarify input constraints and edge cases before writing code.
- Walk through your approach verbally and confirm with the interviewer before coding.
- Start with a brute force solution, then optimize. Mention time and space complexity.
- Test your solution with examples, including edge cases like empty input or duplicates.
- Consider common patterns: sliding window, two pointers, hash map, BFS/DFS, dynamic programming.
Possible Follow-up Questions
- How would you modify your solution to handle streaming input?
- What if the input doesn't fit in memory?
- How would your solution change if the input was sorted?
- What happens if the input contains duplicates?
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Practice DSA ProblemsSample Answer
Problem Analysis
To solve the problem of finding the maximum sum of non-adjacent nodes in a binary tree, we can leverage a recursive approach combined with memoization. The key pattern here is to utilize a depth-first...
Approach
- Define a recursive function
max_sum(node)that returns the maximum sum of non-adjacent nodes considering the subtree rooted atnode. - Base Case: If the
nodeisNone, return 0. - Calc...
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