Week 1

First week of the 30-day plan. Focus: core data structures — arrays, linked lists, stacks, queues, hashing, and trees.

Days and files

Day	Topic	File
1	Review basic data structures (arrays, linked lists, stacks, queues)	day-1-review-basic-data-structures-arrays-linked-lists-stacks-and-queues.md
2	Practice array problems	day-2-practice-array-problems.md
3	Linked list problems	day-3-linked-list-problems.md
4	Stack and queue problems	day-4-stack-and-queue-problems.md
5	Hash tables	day-5-hash-tables.md
6	Review trees basics (binary trees, BST)	page-3.md (Day 6 content)
7	Tree traversal techniques	day-7-tree-traversal-techniques.md

SDE-3 depth

For deeper coverage and interview strategy, use the Foundations topic files:

• Arrays, Linked List, Stack, Queue: foundations/data-structures/

• Hashing: foundations/data-structures/hashing.md

• Trees: foundations/data-structures/tree.md