Design a Food Rating System | LeetCode

題目

https://leetcode.com/problems/design-a-food-rating-system/editorial/?envType=daily-question&envId=2025-09-17

日期

2025/09/17

困惑點

在 LeetCode 的 Swift 語言看起來可以用 swift-collection 的 Heap 。但是不確定是用了哪個版本，用了 removeAll 會報錯說找不到這個方法，但是在 Xcode 裡面卻能夠執行。

程式碼

import Collections

class FoodRatings {

    var cuisineHeaps: [String: Heap<Food>] = [:]
    var foodToCuisine: [String: String] = [:]
    var foodToRating: [String: Int] = [:]

    init(_ foods: [String], _ cuisines: [String], _ ratings: [Int]) {
        for i in foods.indices {
            let ratedFood = Food(food: foods[i], rating: ratings[i])
            cuisineHeaps[cuisines[i], default: Heap()].insert(ratedFood)
            foodToCuisine[foods[i]] = cuisines[i]
            foodToRating[foods[i]] = ratings[i]
        }
    }
    
    func changeRating(_ food: String, _ newRating: Int) {
        guard let cuisine = foodToCuisine[food] else { return }
        let ratedFood = Food(food: food, rating: newRating)
        cuisineHeaps[cuisine]?.removeAll { $0.food == food }
        cuisineHeaps[cuisine]?.insert(ratedFood)
        foodToRating[food] = newRating
    }
    
    func highestRated(_ cuisine: String) -> String {
        cuisineHeaps[cuisine]?.max?.food ?? ""
    }

}

struct Food: Comparable {
    let food: String
    let rating: Int
    static func < (lhs: Food, rhs: Food) -> Bool {
        if lhs.rating == rhs.rating {
            return lhs.food > rhs.food
        } else {
            return lhs.rating < rhs.rating
        }
    }
}