Linkedin SSE Interview

linkedin logo
linkedin
· Senior Software Engineer
March 12, 2026 · 6 reads

Summary

I shared my interview experience, which included a discussion on Java internals covering multi-threading, HashMap, Concurrent HashMap, JVM, and a specific Data Structures & Algorithms question about finding common ancestors in a graph.

Full Experience

Helping Leetcode community !
-------------------------------------------------------------
Dicussion on Java internals (multi threading concepts - Callable/Runnable, HashMap internals, Concurrent HashMap, JVM)

One DSA question asked:

Interview Questions (2)

1.

Java Internals Discussion

Other

Discussion on Java internals including multi-threading concepts (Callable/Runnable), HashMap internals, Concurrent HashMap, and JVM.

2.

Find if Two Individuals Share a Common Ancestor

Data Structures & Algorithms·Medium

Suppose we have some input data describing a graph of relationships between parents and children over multiple generations.
The data is formatted as a list of (parent, child) pairs, where each individual is assigned a unique positive integer identifier.


For example, in this diagram, 6 and 8 have common ancestors of 4 and 14.


15
/ 
14 13 21 | | 1 2 4 12 \ / / | \ / 3 5 8 9 \ / \
6 7 11


pairs = [
(1, 3), (2, 3), (3, 6), (5, 6), (5, 7), (4, 5),
(15, 21), (4, 8), (4, 9), (9, 11), (14, 4), (13, 12),
(12, 9), (15, 13)
]

3: [1,2]
4: [14]
6: [3,5,1,2,4,14]
8:[4,14]



Write a function that takes this data and the identifiers of two individuals as inputs and returns true if and only if they share at least one ancestor.


Sample input and output:


hasCommonAncestor(pairs, 3, 8) => false
hasCommonAncestor(pairs, 5, 8) => true
hasCommonAncestor(pairs, 6, 8) => true
hasCommonAncestor(pairs, 6, 9) => true
hasCommonAncestor(pairs, 1, 3) => false
hasCommonAncestor(pairs, 3, 1) => false
hasCommonAncestor(pairs, 7, 11) => true
hasCommonAncestor(pairs, 6, 5) => true
hasCommonAncestor(pairs, 5, 6) => true
hasCommonAncestor(pairs, 3, 6) => true
hasCommonAncestor(pairs, 21, 11) => true

📣 Found this helpful? Please share it with friends who are preparing for interviews!

Discussion (0)

Share your thoughts and ask questions

Join the Discussion

Sign in with Google to share your thoughts and ask questions

No comments yet

Be the first to share your thoughts and start the discussion!