Data Structures & Algorithms

Master coding interviews with **pattern-first** prep. Understand patterns, practice high-impact curated lists, and learn optimal solutions.

Explore Patterns

Solve linear optimization problems by breaking them into overlapping subproblems and caching states.

3 Easy 18 Medium 1 Hard

Resolve grid navigation and sequence alignment optimizations using 2D state matrices.

12 Medium 4 Hard

Arrays & Hashing

32 problems

Identify duplicates, find frequencies, and achieve constant-time lookups using hash tables.

10 Easy 18 Medium 4 Hard

Backtracking

20 problems

Solve search problems by exploring decision paths and discarding invalid branches.

1 Easy 14 Medium 5 Hard

Binary Search

15 problems

Locate elements in sorted arrays by repeatedly halving the search space range.

4 Easy 8 Medium 3 Hard

Bit Manipulation

10 problems

Solve integer logic and mask operations using low-level bitwise commands.

6 Easy 4 Medium

Graphs

33 problems

Model and traverse networks of nodes connected by symmetric or directed edges.

3 Easy 22 Medium 8 Hard

Greedy

21 problems

Solve optimization problems by making the locally optimal choice at each step.

1 Easy 18 Medium 2 Hard

Heap & Priority Queue

20 problems

Retrieve extreme values in constant time using binary heaps.

2 Easy 12 Medium 6 Hard

Intervals

7 problems

Coordinate overlapping time ranges by sorting boundary points.

1 Easy 4 Medium 2 Hard

Linked List

15 problems

Traverse linear collections of nodes connected by sequential pointer references.

3 Easy 9 Medium 3 Hard

Math & Geometry

16 problems

Solve coordinates, matrix transformations, and numerical algorithms using geometric equations.

6 Easy 9 Medium 1 Hard

Sliding Window

9 problems

Track contiguous subarrays using a dynamic coordinate window that expands and shrinks.

2 Easy 5 Medium 2 Hard

Stack

17 problems

Verify matching parenthetical pairs and track elements using Last-In, First-Out arrays.

4 Easy 10 Medium 3 Hard

Trees

23 problems

Traverse hierarchical node networks representing binary, search, and n-ary structures.

10 Easy 11 Medium 2 Hard

Tries

4 problems

Match character prefixes and store string dictionary keys in nested search trees.

3 Medium 1 Hard

Two Pointers

17 problems

Scan sorted arrays using two coordinate pointers moving from opposite ends or at different speeds.

6 Easy 10 Medium 1 Hard