#2353

Design a Food Rating System

medium · 52.9% accepted · 1,958 likes · top 43%

array · hash table · string · design · heap (priority queue) · ordered set

Description

Design a food rating system that can do the following:

- Modify the rating of a food item listed in the system.

- Return the highest-rated food item for a type of cuisine in the system.

Implement the FoodRatings class:

- FoodRatings(String[] foods, String[] cuisines, int[] ratings) Initializes the system. The food items are described by foods, cuisines and ratings, all of which have a length of n.

- foods[i] is the name of the i^th food,

- cuisines[i] is the type of cuisine of the i^th food, and

- ratings[i] is the initial rating of the i^th food.

- void changeRating(String food, int newRating) Changes the rating of the food item with the name food.

- String highestRated(String cuisine) Returns the name of the food item that has the highest rating for the given type of cuisine. If there is a tie, return the item with the lexicographically smaller name.

Note that a string x is lexicographically smaller than string y if x comes before y in dictionary order, that is, either x is a prefix of y, or if i is the first position such that x[i] != y[i], then x[i] comes before y[i] in alphabetic order.

Example 1:

Input

["FoodRatings", "highestRated", "highestRated", "changeRating", "highestRated", "changeRating", "highestRated"]

[[["kimchi", "miso", "sushi", "moussaka", "ramen", "bulgogi"], ["korean", "japanese", "japanese", "greek", "japanese", "korean"], [9, 12, 8, 15, 14, 7]], ["korean"], ["japanese"], ["sushi", 16], ["japanese"], ["ramen", 16], ["japanese"]]

Output

[null, "kimchi", "ramen", null, "sushi", null, "ramen"]

Example 2:

Explanation

FoodRatings foodRatings = new FoodRatings(["kimchi", "miso", "sushi", "moussaka", "ramen", "bulgogi"], ["korean", "japanese", "japanese", "greek", "japanese", "korean"], [9, 12, 8, 15, 14, 7]);

foodRatings.highestRated("korean"); // return "kimchi"

// "kimchi" is the highest rated korean food with a rating of 9.

foodRatings.highestRated("japanese"); // return "ramen"

// "ramen" is the highest rated japanese food with a rating of 14.

foodRatings.changeRating("sushi", 16); // "sushi" now has a rating of 16.

foodRatings.highestRated("japanese"); // return "sushi"

// "sushi" is the highest rated japanese food with a rating of 16.

foodRatings.changeRating("ramen", 16); // "ramen" now has a rating of 16.

foodRatings.highestRated("japanese"); // return "ramen"

// Both "sushi" and "ramen" have a rating of 16.

// However, "ramen" is lexicographically smaller than "sushi".

Solution