Detect Circular Money Flows in a Payment Transaction Graph

Problem Given a list of payment transactions [senderId, receiverId, amount], detect all cycles in the directed transaction graph — circular money flows that may signal fraud or represent netted settlement rings. Return the full cycle path, not just a boolean.

Input / Output

• Input: list of [senderId, receiverId, amount] edges.
• Output: the cycles found, each as the ordered list of accounts on the cycle.

Constraints

• Up to 10^5 transactions.
• Account IDs are strings (UUIDs in production).

Example

• transactions = [["A","B",100],["B","C",200],["C","A",150],["D","E",50]] → [["A","B","C"]] (cycle A→B→C→A).