CMSC 12 - 2nd Exam - Problem Solving

# Function for counting and returning the 2 most instances in a given list parameter
def count(list1):

    # initialize dictionary (dict is not recommended name for the dictionary as it might cause some errors)
    dict = {}

    # count
    for element in list1:
        if element in dict:
            dict[element] += 1
        else:
            dict[element] = 1

    # initialize elements and corresponding values to compare
    element1 = "None"       # String None to annotate
    element2 = "None"
    first = 0
    second = 0

    if len(dict) > 0:
        for key in dict:
            if dict[key] > first:
                element2 = element1
                second = first
                element1 = key
                first = dict[key]
            elif dict[key] > second:
                element2 = key
                second = dict[key]

    # put results in a list
    output = [element1, element2]

    return output


# Main part
list1 = ["a","a","a","b","c","c","d","d","d","d","b","a"]
output = count(list1)
print("The two items with most instances are "+output[0]+" and "+output[1])