Darbar 005 — Check If N And Its Double Exist
Easy
Darbar · Array
Catalog slot 5 of 548 (source id 228). Topic array / binary search.
Solve on LeetCode: Check If N And Its Double Exist. 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: Timed routing (weeks 1-15, slots 1-120). Warmup: LeetCode-style easy problems (15 min each). Exam: Weekly timed block, 3-5 problems in 60 minutes.
Also filed under: hash table / binary search, hash table / two pointer.
Evidence (cookiecutter problem_005.md)
- Attempt log (approaches that failed)
- Final complexity (time and space)
- One mistake corrected
- Production concept this slot reinforces
Personal dates and the CSV tracker stay in the learner journal.
Same subtopic
- Find Target Indices After Sorting Array · easy
- Count Negative Numbers In A Sorted Matrix · easy
- The K Weakest Rows In A Matrix · easy
- Search Insert Position · easy
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