2353.java

import java.util.HashMap;
import java.util.Map;
import java.util.PriorityQueue;
import java.util.Queue;

public class FoodRatings {
    
    private class Food implements Comparable<Food>{
        // skip boilerplate getter/setters
        public String food;
        public String cuisine;
        public int rating;

        public Food(String food, String cuisine, int rating) {
            this.food = food;
            this.cuisine = cuisine;
            this.rating = rating;
        }

        @Override
        public int compareTo(Food o) {
            assert o != null;
            if (o.rating == this.rating) {
                return this.food.compareTo(o.food);
            }
            return o.rating - this.rating; }
    }

    // food -> Food
    private Map<String, Food> foodIndex = new HashMap<>();
    // cuisine -> MaxHeap on rating
    private Map<String, Queue<Food>> cuisineIndex = new HashMap<>();

    public FoodRatings(String[] foods, String[] cuisines, int[] ratings) {
        for (int i = 0; i < foods.length; i++) {
            Food f = new Food(foods[i], cuisines[i], ratings[i]);
            // given food is distinct

            this.foodIndex.put(f.food, f);
            /* use putIfAbsent instead
            if (!this.cuisineIndex.containsKey(f.cuisine)) {
                this.cuisineIndex.put(f.cuisine, new PriorityQueue<>());
            }
            */
            this.cuisineIndex.putIfAbsent(f.cuisine, new PriorityQueue<>());
            this.cuisineIndex.get(f.cuisine).add(f);
        }
    }

    public void changeRating(String food, int newRating) {
        Food f = this.foodIndex.get(food);
        f.rating = newRating;
        // need to update the max heap by deleting and re-inserting
        this.cuisineIndex.get(f.cuisine).remove(f);
        this.cuisineIndex.get(f.cuisine).add(f);
    }

    public String highestRated(String cuisine) {
        return this.cuisineIndex.get(cuisine).peek().food;
    }

}