Expense Ledger

A company's expense tracking database was lost. Fortunately, a complete historical log of all financial transactions was retained. Your task is to reconstruct each user's final expense status from this transaction history.

You are given a 2D list of unordered transactions, where each element represents a single transaction for one user. Each transaction may record an expense charge, a reimbursement, or both. Some monetary fields may be missing (provided as "") and should be ignored. ...