Explore

Arrays

A row of lockers for your data

10 LeetCode 3–5 hours

Linked List

Connected nodes forming a chain

10 LeetCode 4–6 hours

Stacks

Last In First Out structure

10 LeetCode 3–4 hours

Queues

First In First Out structure

10 LeetCode 3–4 hours

HashMap & HashSet

Fast lookup using keys

13 LeetCode 4–6 hours

Sorting Algorithms

Arrange data in order

10 LeetCode 6–10 hours

Search Algorithms

Find items efficiently

10 LeetCode 5–9 hours

String Manipulation

Transform and analyze text

10 LeetCode 6–10 hours

Data StructureIntermediate

Two Pointers

Two indices moving through data in tandem

5 LeetCode 4–6 hours

Intermediate

Binary Trees

Hierarchical node-based structure

13 LeetCode 6–8 hours

Data StructureIntermediate

Heaps

Priority-based tree structure

10 LeetCode 5–7 hours

Data StructureIntermediate

Graphs (BFS/DFS)

Nodes connected with edges

12 LeetCode 6–9 hours

Dynamic Programming

Break problems into overlapping subproblems

18 LeetCode 8–12 hours

Sliding Window

Maintain a moving subarray over data

6 LeetCode 5–7 hours

Backtracking

Explore all possibilities, prune dead ends

10 LeetCode 6–9 hours

Greedy Algorithms

Make the locally optimal choice at each step

6 LeetCode 5–7 hours

Bit Manipulation

Operate directly on binary representations

5 LeetCode 4–6 hours

Recursion & Divide and Conquer

Split problems, solve halves, combine results

5 LeetCode 5–8 hours

Matrix & 2D Arrays

Grid traversal, rotation, and DP on 2D

5 LeetCode 5–7 hours

Intervals

Merge, insert and count overlapping ranges

5 LeetCode 4–6 hours

Advanced

AVL Trees

Self-balancing binary search trees

10 LeetCode 8–12 hours

Tries

Prefix-based word lookup tree

10 LeetCode 6–10 hours

AlgorithmAdvanced

Advanced Graph Algorithms

Shortest paths and connectivity

10 LeetCode 8–15 hours

Segment Trees

Range queries and updates in O(log n)

3 LeetCode 8–12 hours