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| 1 | +<h2><a href="https://leetcode.com/problems/design-a-food-rating-system/?envType=daily-question&envId=2025-09-17">2429. Design a Food Rating System</a></h2><h3>Medium</h3><hr><p>Design a food rating system that can do the following:</p> |
| 2 | + |
| 3 | +<ul> |
| 4 | + <li><strong>Modify</strong> the rating of a food item listed in the system.</li> |
| 5 | + <li>Return the highest-rated food item for a type of cuisine in the system.</li> |
| 6 | +</ul> |
| 7 | + |
| 8 | +<p>Implement the <code>FoodRatings</code> class:</p> |
| 9 | + |
| 10 | +<ul> |
| 11 | + <li><code>FoodRatings(String[] foods, String[] cuisines, int[] ratings)</code> Initializes the system. The food items are described by <code>foods</code>, <code>cuisines</code> and <code>ratings</code>, all of which have a length of <code>n</code>. |
| 12 | + |
| 13 | + <ul> |
| 14 | + <li><code>foods[i]</code> is the name of the <code>i<sup>th</sup></code> food,</li> |
| 15 | + <li><code>cuisines[i]</code> is the type of cuisine of the <code>i<sup>th</sup></code> food, and</li> |
| 16 | + <li><code>ratings[i]</code> is the initial rating of the <code>i<sup>th</sup></code> food.</li> |
| 17 | + </ul> |
| 18 | + </li> |
| 19 | + <li><code>void changeRating(String food, int newRating)</code> Changes the rating of the food item with the name <code>food</code>.</li> |
| 20 | + <li><code>String highestRated(String cuisine)</code> Returns the name of the food item that has the highest rating for the given type of <code>cuisine</code>. If there is a tie, return the item with the <strong>lexicographically smaller</strong> name.</li> |
| 21 | +</ul> |
| 22 | + |
| 23 | +<p>Note that a string <code>x</code> is lexicographically smaller than string <code>y</code> if <code>x</code> comes before <code>y</code> in dictionary order, that is, either <code>x</code> is a prefix of <code>y</code>, or if <code>i</code> is the first position such that <code>x[i] != y[i]</code>, then <code>x[i]</code> comes before <code>y[i]</code> in alphabetic order.</p> |
| 24 | + |
| 25 | +<p> </p> |
| 26 | +<p><strong class="example">Example 1:</strong></p> |
| 27 | + |
| 28 | +<pre> |
| 29 | +<strong>Input</strong> |
| 30 | +["FoodRatings", "highestRated", "highestRated", "changeRating", "highestRated", "changeRating", "highestRated"] |
| 31 | +[[["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"]] |
| 32 | +<strong>Output</strong> |
| 33 | +[null, "kimchi", "ramen", null, "sushi", null, "ramen"] |
| 34 | + |
| 35 | +<strong>Explanation</strong> |
| 36 | +FoodRatings foodRatings = new FoodRatings(["kimchi", "miso", "sushi", "moussaka", "ramen", "bulgogi"], ["korean", "japanese", "japanese", "greek", "japanese", "korean"], [9, 12, 8, 15, 14, 7]); |
| 37 | +foodRatings.highestRated("korean"); // return "kimchi" |
| 38 | + // "kimchi" is the highest rated korean food with a rating of 9. |
| 39 | +foodRatings.highestRated("japanese"); // return "ramen" |
| 40 | + // "ramen" is the highest rated japanese food with a rating of 14. |
| 41 | +foodRatings.changeRating("sushi", 16); // "sushi" now has a rating of 16. |
| 42 | +foodRatings.highestRated("japanese"); // return "sushi" |
| 43 | + // "sushi" is the highest rated japanese food with a rating of 16. |
| 44 | +foodRatings.changeRating("ramen", 16); // "ramen" now has a rating of 16. |
| 45 | +foodRatings.highestRated("japanese"); // return "ramen" |
| 46 | + // Both "sushi" and "ramen" have a rating of 16. |
| 47 | + // However, "ramen" is lexicographically smaller than "sushi". |
| 48 | +</pre> |
| 49 | + |
| 50 | +<p> </p> |
| 51 | +<p><strong>Constraints:</strong></p> |
| 52 | + |
| 53 | +<ul> |
| 54 | + <li><code>1 <= n <= 2 * 10<sup>4</sup></code></li> |
| 55 | + <li><code>n == foods.length == cuisines.length == ratings.length</code></li> |
| 56 | + <li><code>1 <= foods[i].length, cuisines[i].length <= 10</code></li> |
| 57 | + <li><code>foods[i]</code>, <code>cuisines[i]</code> consist of lowercase English letters.</li> |
| 58 | + <li><code>1 <= ratings[i] <= 10<sup>8</sup></code></li> |
| 59 | + <li>All the strings in <code>foods</code> are <strong>distinct</strong>.</li> |
| 60 | + <li><code>food</code> will be the name of a food item in the system across all calls to <code>changeRating</code>.</li> |
| 61 | + <li><code>cuisine</code> will be a type of cuisine of <strong>at least one</strong> food item in the system across all calls to <code>highestRated</code>.</li> |
| 62 | + <li>At most <code>2 * 10<sup>4</sup></code> calls <strong>in total</strong> will be made to <code>changeRating</code> and <code>highestRated</code>.</li> |
| 63 | +</ul> |
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