def first_recurring_character2(array):
    """
    - Create a dictionary
    - Loop through the list
    - At each item
    - check if item in dictionary
        - if present => return true
    - else dictionary[item] = True

    O(n) - worst case will check each element once
    """
    items_already_seen = {}
    for item in array:
        if items_already_seen.get(item): 
            return item
        else:
            items_already_seen[item] = True