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A payment ledger records each transaction event with a timestamp and amount.
Table: transactions
Task: For every calendar date, identify the transaction(s) with the highest amount on that date.
Rules:
Output requirements:
Supported submission environments:
transactions:
| transaction_id | day | amount |
|----------------|---------------------|--------|
| 8 | 2021-04-03 15:57:28 | 57 |
| 9 | 2021-04-28 08:47:25 | 21 |
| 1 | 2021-04-29 13:28:30 | 58 |
| 5 | 2021-04-28 16:39:59 | 40 |
| 6 | 2021-04-29 23:39:28 | 58 |[
{"transaction_id":1},
{"transaction_id":5},
{"transaction_id":6},
{"transaction_id":8}
]Explanation
Daily winners are: 2021-04-03 -> {8}, 2021-04-28 -> {5}, 2021-04-29 -> {1, 6}. The final output is globally sorted by transaction_id.
transactions:
| transaction_id | day | amount |
|----------------|---------------------|--------|
| 101 | 2024-01-11 00:00:01 | -5 |
| 102 | 2024-01-11 23:59:59 | -2 |
| 103 | 2024-01-12 09:30:00 | 10 |
| 104 | 2024-01-12 11:45:00 | 10 |
| 105 | 2024-01-12 19:05:00 | 7 |[
{"transaction_id":102},
{"transaction_id":103},
{"transaction_id":104}
]Explanation
For 2024-01-11, -2 is the maximum. For 2024-01-12, two rows tie at amount 10, so both IDs are returned.
transactions:
| transaction_id | day | amount |
|----------------|---------------------|--------|
| 7001 | 2025-07-01 12:00:00 | 500 |
| 7002 | 2025-07-02 12:00:00 | 450 |
| 7003 | 2025-07-03 12:00:00 | 600 |
| 7004 | 2025-07-03 23:59:58 | 600 |[
{"transaction_id":7001},
{"transaction_id":7002},
{"transaction_id":7003},
{"transaction_id":7004}
]Explanation
Every date contributes at least one winner. On 2025-07-03, both 7003 and 7004 share the daily peak.
Constraints