Pairs

Consider two arrays of integers, a[n] and b[n]. What is the maximum number of pairs that can be formed where a[i] > b[j]?
Each element can be in no more than one pair.

Find the maximum number of such possible pairs.

Swap Parity

Given a number num, two adjacent digits can be swapped if their parity is the same, that is, both are odd or both are even. For example, (5, 9) have the same parity, but (6,9) do not.

Find the largest number that can be created. The swap operation can be applied any number of times.