[FE] Ismayil Aghazada (ismayil.aqazade@gmail.com)

[IsmayilAghazada]

Problem 1

• Implemented sum_to_n in three ways: iterative (sum_to_n_a), closed form (n(n+1)/2) (sum_to_n_b), and recursive (sum_to_n_c).
• Shared input validation: finite integers only; non-numbers, NaN, infinities, and non-integers throw clear TypeError messages; n < 1 returns 0.
• sum_to_n.test.ts: Vitest coverage for all three implementations (correctness vs naive reference, edge cases, runtime validation, cross-implementation agreement).

Problem 2

• Vite + React 19 swap form: fetches prices.json, dedupes/sorts price rows, omits tokens without usable data.
• Chakra UI v3 with a custom createSystem theme (tokens, fonts, swap-specific radii/shadows).
• React Hook Form for amount validation, loading/error states, flip pay/receive, live output and rate hints via useSwapUI, token icons from the Switcheo token-icons base URL (configurable with VITE_* env vars).
• Docker: multi-stage build + nginx under src/problem2/docker/; root package.json scripts docker:build:problem2 and docker:run:problem2.

Problem 3

• Refactor of the “messy React” wallet list: fixes undefined lhsPriority, inverted filter logic for non-positive amounts, any typing, and getPriority recreated every render.
• walletRowPipeline.ts: pure pipeline (filter eligible rows by chain priority + positive amount, sort, map to view models with formatted amount and USD value) for testability and separation from React.
• models.ts / consts.ts: typed Blockchain / WalletBalance, priority map at module scope.
• page.tsx: composes hooks + pipeline with useMemo for row elements; WalletRow.tsx presentational row; stub hooks.ts for balances/prices.
• README.md in Problem 3 documents issues vs fixes (code review style).