To be pedantic, this isn't the operation he gave - "split an integer into 2 smaller integers" is the operation, but 2 into [3, -1] is splitting it into a larger

To be pedantic, this isn't the operation he gave - "split an integer into 2 smaller integers" is the operation, but 2 into [3, -1] is splitting it into a larger and smaller integer. Read literally, the numbers are constrained to not jump over the 0. It might depend on interpretation (absolute value or distance from positive infinity?); but negatives are tricky to handle with these rules and I think they might be illegal.