设计食物评分系统

/*
 * 思路：
 * 1. 使用 HashMap 存储食物到评分和食物到烹饪方式的映射。
 * 2. 使用 TreeSet 存储每种烹饪方式下的食物，TreeSet 以评分为主要排序，
 *    字典序为次要排序。
 * 3. changeRating 方法使用 Java Stream 操作，更新评分后重新插入 TreeSet。
 * 4. highestRated 方法直接从 TreeSet 获取评分最高的食物。
 */
import java.util.*;
import java.util.stream.*;

class FoodRatings {
    private Map<String, String> foodToCuisine;
    private Map<String, Integer> foodToRating;
    private Map<String, TreeSet<String>> cuisineToFoods;

    public FoodRatings(String[] foods, String[] cuisines, int[] ratings) {
        foodToCuisine = new HashMap<>();
        foodToRating = new HashMap<>();
        cuisineToFoods = new HashMap<>();
        for (int i = 0; i < foods.length; i++) {
            foodToCuisine.put(foods[i], cuisines[i]);
            foodToRating.put(foods[i], ratings[i]);
            cuisineToFoods.computeIfAbsent(cuisines[i], k -> new TreeSet<>((a, b) -> {
                int ratingA = foodToRating.get(a);
                int ratingB = foodToRating.get(b);
                if (ratingA == ratingB) {
                    return a.compareTo(b);
                }
                return Integer.compare(ratingB, ratingA);
            })).add(foods[i]);
        }
    }

    public void changeRating(String food, int newRating) {
        String cuisine = foodToCuisine.get(food);
        TreeSet<String> foodSet = cuisineToFoods.get(cuisine);
        foodSet.remove(food);  // 先移除旧的评分
        foodToRating.put(food, newRating);  // 更新评分
        foodSet.add(food);  // 重新加入以保持排序
    }

    public String highestRated(String cuisine) {
        return cuisineToFoods.get(cuisine).first();
    }
}