The data team is comparing two versions of a one-column dataset: src and tgt, each containing values in k.
A value may occur several times in either table. The team needs to identify the extra copies present in src compared with tgt.
For each value, one occurrence in tgt accounts for one matching occurrence in src. Report every remaining occurrence from src as a separate row. If a value has no surplus copies, it should not appear.
Ordering: Sort by k in ascending order. Return one row per surplus copy.