You are given two arrays of positive integers, arr1 and arr2.

A prefix of a positive integer is an integer formed by one or more of its digits, starting from the leftmost digit. For example, $123$ is a prefix of $12345$, while $234$ is not.

A common prefix of two integers $a$ and $b$ is an integer $c$, such that $c$ is a prefix of both $a$ and $b$. For example,  ...