GuillaumeTong

# this function expects array1 and array2 to be iterables containing capital letter characters
def isSubset(array1, array2):
    hashtable = dict.fromkeys(array1, True)
    for x in array2:
        if not hashtable.__contains__(x):
            return False
    return True

# # By using dict to store array1, we can get hashtable key lookup performance, which is O(1). Based on this,
# # the complexity of the function is overall O(n), as both array1 and array2 are only traversed once, and only an O(1)