[C++]Number of Cases in 2D Vector

Congratulations!

You’ve got the free toppings you can put on a pizza. You may want to select at least one topping from the table below, but the same type of toppings cannot be chosen. Then, How many numbers of cases exist?

Type	Name
Meats	Bacon, Sausage, Chicken
Seafoods	Shrimp
Veggies	Onion, Mushroom
Cheeses	Provolone

First of all, we have to consider the case that only one topping is selected. So, the number of toppings in the same type will be counted, and add 1 to the count for each unchosen type of topping.

int solution(vector<vector<string>> toppings) {
    int answer = 1;
    unordered_map<string, int>solution_map;
    for(auto t : toppings){
        solution_map[t[1]]++;
    }//Meats = 3, Seafoods = 1, Veggies = 2, Cheeses = 1
    for(auto pair : solution_map){
        answer *= pair.second + 1;
    }
    return answer - 1;
}

The reason of subtracting 1 from answer is to except the case that none of toppings is not be chosen.

There are total 47 options for you.

Enjoy Pizza Night!