Pick one surviving record per account

The rules

These rules decide what a correct result is. Your answer is checked on this dataset and on hidden datasets that follow the same rules.

Input
  records(id, account, updated, priority) — all text. id is unique. account keeps its leading zeros.
  updated is an ISO 8601 timestamp with an explicit offset; priority is a whole number. Both are always present and valid.

Rule
  Keep one row per account. The survivor is the row with:
    1. the latest updated instant (compare instants, not text: 01:00+01:00 equals 00:00Z),
    2. then the higher priority,
    3. then the lowest id (code-point order).
  Every other row goes to exceptions with reason "duplicate".

Outputs (row order does not matter)
  clean(id text, account text, updated timestamptz [UTC], priority int64)
  exceptions(id text, reason text)