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Square (Block) Interview Question Bank

Block (Square, Cash App) screens with practical, multi-part CoderPad problems modeled on real product logic, where tests and clean refactoring between parts matter as much as the algorithm. Senior loops add a conversational round on AI-native engineering workflow, and money-movement teams probe correctness, legacy tech debt, and regulated-system judgment.

Coding problems
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Coding·60 min
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Customer Transaction Network

Three-part CoderPad screen: (1) a class that records customer-to-customer transactions and answers whether two customers have ever transacted together; (2) findNetwork(customer) returning everyone transitively connected; (3) findNetwork(customer, n) limited to n degrees of separation. Build an undirected graph, then BFS, then BFS with depth.

SWE
graph
bfs
hashmap
testing
+2
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