2022.07.24 (lc_6126_design food scoring system)

  Method ：Map+TreeSet

class FoodRatings {
    // Use a food information class to represent the food name of food 、 The way of cooking 、 score 
    class FoodInfo {
        String food;
        String cuisine;
        int rating;
        FoodInfo(String food, String cuisine, int rating) {
            this.food = food;
            this.cuisine = cuisine;
            this.rating = rating;
        }
    }
    // The food name corresponds to a food information class 
    Map<String, FoodInfo> foodInfoMap = new HashMap<>();
    // The cooking method corresponds to one TreeSet,TreeSet Store all this cooking , And customize the sorting according to the meaning of the topic 
    Map<String, TreeSet<FoodInfo>> cuisineMap = new HashMap<>();
    public FoodRatings(String[] foods, String[] cuisines, int[] ratings) {
        for (int i = 0; i < foods.length; i++) {
            FoodInfo foodInfo = new FoodInfo(foods[i], cuisines[i], ratings[i]);
            foodInfoMap.put(foods[i], foodInfo);
            if (!cuisineMap.containsKey(cuisines[i])) {
                cuisineMap.put(cuisines[i], new TreeSet<>(((o1, o2) -> {
                    // Sorting rules for foods cooked in the same way ： First, arrange them in descending order ,
                    // If the score is the same , Then arrange the food names in ascending order according to the dictionary .
                    if (o1.rating != o2.rating) return o2.rating - o1.rating;
                    return o1.food.compareTo(o2.food);
                })));
            }
            // In the way of cooking TreeSet Add food information to 
            cuisineMap.get(cuisines[i]).add(foodInfo);
        }
    }
    
    public void changeRating(String food, int newRating) {
        FoodInfo foodInfo = foodInfoMap.get(food);
        // When changing the score, you need to put TreeSet Delete the scoring information in , Otherwise, it is wrong to change the position after scoring 
        // Delete first , Then change the score , Finally add TreeSet Find the right position 
        cuisineMap.get(foodInfo.cuisine).remove(foodInfo);
        foodInfo.rating = newRating;
        cuisineMap.get(foodInfo.cuisine).add(foodInfo);
    }
    
    public String highestRated(String cuisine) {
        // Directly return to the corresponding cooking method TreeSet The first food name of 
        return cuisineMap.get(cuisine).first().food;
    }
}

Be careful ：

• When updating the score Delete and then re insert , Trigger the rotation of nodes in the red black tree .