Find the maximum element which is common in two arrays?

Question

Given two arrays, how to find the maximum element which is common to both the arrays?

I was thinking of sorting both the arrays(n log n) and then perform the binary sear

Answer 1

Not a perfect, but a simple solution, O(len(array1) + len(array2))

import sys


def find_max_in_common(array1, array2):
    array1 = set(array1)
    array2 = set(array2)

    item_lookup = {}

    for item in array1:
        item_lookup[item] = True

    max_item = -sys.maxsize

    intersection = False

    for item in array2:
        if not item_lookup.get(item, None):
            continue
        else:
            intersection = True
            if item > max_item:
                max_item = item

    return None if not intersection else max_item