Darbar 221 — Contains Duplicate Ii

Easy

Darbar · Hash Table

Catalog slot 221 of 548 (source id 700). Topic hash table / sliding window.

Solve on LeetCode: Contains Duplicate Ii. Do not treat this page as a statement dump.

Aligned T2T band: weeks 1–6. Start at Week 1. Full map: Darbar hub.

Pattern block: Tree and graph fluency (weeks 31-45, slots 201-280). Warmup: Tree traversals and adjacency-list graph walks. Exam: Tree+graph block with one design flavored problem.

Evidence (cookiecutter problem_221.md)

1. Attempt log (approaches that failed)
2. Final complexity (time and space)
3. One mistake corrected
4. Production concept this slot reinforces

Personal dates and the CSV tracker stay in the learner journal.

Same subtopic

• Substrings Of Size Three With Distinct Characters · easy
• Number Of Substrings Containing All Three Characters · medium
• Sliding Window Median · hard
• Minimum Window Substring · hard

Hash Table index · Darbar hub

Darbar slot 221 of Tensor-to-Tenant · Previous · Next.