2023-12-17 09:09:37 +0000 UTC

class Food:
    def __init__(self, food_rating, food_name):
        # Store the food's rating.
        self.food_rating = food_rating
        # Store the food's name.
        self.food_name = food_name

    def __lt__(self, other):
        # Overload the less than operator for comparison.
        # If food ratings are the same, sort based on their name (lexicographically smaller name food will be on top).
        if self.food_rating == other.food_rating:
            return self.food_name < other.food_name
        # Sort based on food rating (bigger rating food will be on top).
        return self.food_rating > other.food_rating

class FoodRatings:
    def __init__(self, foods: List[str], cuisines: List[str], ratings: List[int]):
        # Map food with its rating.
        self.food_rating_map = {}
        # Map food with the cuisine it belongs to.
        self.food_cuisine_map = {}
        # Store all food of a cuisine in a priority queue (to sort them on ratings/name).
        # Priority queue element -> Food: (food_rating, food_name)
        self.cuisine_food_map = defaultdict(list)

        for i in range(len(foods)):
            # Store 'rating' and 'cuisine' of the current 'food' in 'food_rating_map' and 'food_cuisine_map' maps.
            self.food_rating_map[foods[i]] = ratings[i]
            self.food_cuisine_map[foods[i]] = cuisines[i]
            # Insert the '(rating, name)' element into the current cuisine's priority queue.
            heapq.heappush(self.cuisine_food_map[cuisines[i]], Food(ratings[i], foods[i]))

    def changeRating(self, food: str, newRating: int) -> None:
        # Update food's rating in 'food_rating' map.
        self.food_rating_map[food] = newRating
        # Insert the '(new rating, name)' element in the respective cuisine's priority queue.
        cuisineName = self.food_cuisine_map[food]
        heapq.heappush(self.cuisine_food_map[cuisineName], Food(newRating, food))

    def highestRated(self, cuisine: str) -> str:
        # Get the highest rated 'food' of 'cuisine'.
        highest_rated = self.cuisine_food_map[cuisine][0]

        # If the latest rating of 'food' doesn't match with the 'rating' on which it was sorted in the priority queue,
        # then we discard this element from the priority queue.
        while self.food_rating_map[highest_rated.food_name] != highest_rated.food_rating:
            heapq.heappop(self.cuisine_food_map[cuisine])
            highest_rated = self.cuisine_food_map[cuisine][0]

        # Return the name of the highest-rated 'food' of 'cuisine'.
        return highest_rated.food_name