Keyset pagination continues after the last row from the previous page instead of skipping an offset. A compound cursor is required when the primary sort column is not unique.
Design a KeysetPaginator class:
KeysetPaginator() creates a stateless paginator.int[] nextPage(int[] timestamps, int[] ids, int cursorTimestamp, int cursorId, int limit) returns up to limit row IDs strictly after the cursor.
The aligned rows are already sorted by timestamp descending, then ID descending. A row (timestamp, id) is after the cursor when:
timestamp < cursorTimestamp, ortimestamp == cursorTimestamp and id < cursorId.
The special cursor (-1,-1) means before the first row and requests the first page. A non-sentinel cursor need not appear in the data.
Example 1:
Input:
Output:
Explanation: The next rows after (100,5) are (90,9) and (90,7).
Example 2:
Input:
Output:
Explanation: Even though (90,8) is absent, binary search begins at the first row ordered after it.
Constraints
0 <= timestamps.length == ids.length <= 10^50 <= timestamps[i], ids[i] <= 10^9- Rows are sorted by
(timestamp DESC, id DESC) and IDs are unique. - The cursor is
(-1,-1) or has non-negative components. 0 <= limit <= 10^5
Page with a Compound Keyset Cursormedium