Compute Balances and Minimize Settlements

You are building a daily ledger service. A transaction record has three fields: `timestamp`, `user_id`, and `delta_amount`. `delta_amount` can be positive or negative and represents how that user's balance changes during the day. All amounts are integers. 1. Given a list of transaction records for a single day, compute each user's end-of-day net balance, assuming every user's starting balance is 0. 2. Using the resulting balances, generate a settlement plan with the minimum possible number of transfers so that every user's final balance becomes 0. A user with a negative balance must pay money, and a user with a positive balance must receive money. Each settlement transfer should be represented as `(from_user, to_user, amount)`. Notes: - Users whose balance is 0 do not need to appear in the settlement plan. - You may assume the sum of all balances is 0. - For the exact-minimum settlement part, assume the number of users with non-zero balance is small enough to permit an exponential-search solution if needed.