UNDERSTAND. EXPLAIN. REPEAT.
Question library
Explained questions for the decisions developers make.
660 questions
Trees and binary search trees
Binary tree
Intermediate2 min read
Heap and priority queue
What it is
Intermediate2 min read
Graphs
Graph representation
Intermediate2 min read
Dynamic programming
What it is
Intermediate2 min read
Greedy algorithms
What it is
Intermediate2 min read
Sorting and searching
Sorting
Intermediate2 min read
Bit manipulation
Important concepts
Advanced2 min read
Sliding window and two pointers
Sliding window
Advanced2 min read
Advanced patterns
Monotonic stack
Advanced2 min read
Common interview topics by priority
Must know
Advanced2 min read
30 interview questions to practice
1. Two Sum
Advanced2 min read
Final interview advice
Explain the approach before coding.
Advanced2 min read
Java DSA basics
Common data structures in Java
Foundation2 min read
Arrays and strings in Java
Key operations
Foundation2 min read
Hashing and maps in Java
Why it matters
Foundation2 min read
Linked list in Java
Node structure
Foundation2 min read
Stack and queue in Java
Stack
Intermediate2 min read
Recursion and backtracking in Java
Common questions
Intermediate2 min read
Difficulty is an editorial estimate. Completion means you chose to mark a question as understood.