Leetcode-6126: designing a food scoring system

subject

Topic linking

Problem solving

Method 1 ： Orderly map+ Orderly set

According to the way of cooking , You can get dishes and corresponding scores , Choose the one with the highest score .
1. use first unordered_map<string,XXXX> according to The way of cooking , Get the corresponding Dishes and scores .
2. So how to get score The biggest , You can use order map（ Red and black trees ）, With score As key, Sort from large to small .
So there is map<int,XXXX,greater<int>>, So you can get the corresponding dishes by scoring
3. In order to ensure that the dishes are dictionary order , So use ordered sets , Sort from small to large ,set<string>
therefore
unordered_map<string,map<int,set<string>,greater<int>>> map;
It can be based on The way of cooking ----> Maximum score ----> The one with the smallest dictionary order

class FoodRatings {
    
public:
    map<string,int> foodRating;// variety of dishes ---> score 
    map<string,string> foodClass;// variety of dishes --> The way of cooking 
    unordered_map<string,map<int,set<string>,greater<int>>> map;// The way of cooking ----> score （ From big to small ）----> variety of dishes 
    FoodRatings(vector<string>& foods, vector<string>& cuisines, vector<int>& ratings) {
    
        for(int i=0;i<foods.size();i++){
    
            foodRating[foods[i]]=ratings[i];
            foodClass[foods[i]]=cuisines[i];
            map[cuisines[i]][ratings[i]].insert(foods[i]);
        }
    }
    
    void changeRating(string food, int newRating) {
    
    	// Delete the corresponding old dish score from the set 
        map[foodClass[food]][foodRating[food]].erase(food);
        if(map[foodClass[food]][foodRating[food]].empty()){
    // If the corresponding score map It's empty , Then delete the map
            map[foodClass[food]].erase(foodRating[food]);
        }
        // Record the score of new dishes 
        foodRating[food]=newRating;
        map[foodClass[food]][newRating].insert(food);
    }
    
    string highestRated(string cuisine) {
    
        return *(map[cuisine].begin()->second.begin());
    }
};