Create design-a-food-rating-system.py

Author: kamyu104

Python/design-a-food-rating-system.py

@@ -0,0 +1,45 @@
+# Time:  ctor:         O(nlogn)
+#        changeRating: O(logn)
+#        highestRated: O(1)
+# Space: O(n)
+
+import collections
+import itertools
+from sortedcontainers import SortedList
+
+
+# sorted list
+class FoodRatings(object):
+
+    def __init__(self, foods, cuisines, ratings):
+        """
+        :type foods: List[str]
+        :type cuisines: List[str]
+        :type ratings: List[int]
+        """
+        self.__food_to_cuisine = {}
+        self.__food_to_rating = {}
+        self.__cusine_to_rating_foods = collections.defaultdict(SortedList)
+        for food, cuisine, rating in itertools.izip(foods, cuisines, ratings):
+            self.__food_to_cuisine[food] = cuisine
+            self.__food_to_rating[food] = rating
+            self.__cusine_to_rating_foods[cuisine].add((-rating, food))
+
+    def changeRating(self, food, newRating):
+        """
+        :type food: str
+        :type newRating: int
+        :rtype: None
+        """
+        old_rating = self.__food_to_rating[food]
+        cuisine = self.__food_to_cuisine[food]
+        self.__cusine_to_rating_foods[cuisine].remove((-old_rating, food))
+        self.__food_to_rating[food] = newRating
+        self.__cusine_to_rating_foods[cuisine].add((-newRating, food))
+
+    def highestRated(self, cuisine):
+        """
+        :type cuisine: str
+        :rtype: str
+        """
+        return self.__cusine_to_rating_foods[cuisine][0][1]