1244

leetcode/1244. Design A Leaderboard/README.md

@@ -0,0 +1,88 @@
+# [1244. Design A Leaderboard (Medium)](https://leetcode.com/problems/design-a-leaderboard/)
+
+<p>Design a Leaderboard class, which has 3 functions:</p>
+
+<ol>
+	<li><code>addScore(playerId, score)</code>: Update the leaderboard by adding <code>score</code> to the given player's score. If there is no player with such id in the leaderboard, add him to the leaderboard with the given <code>score</code>.</li>
+	<li><code>top(K)</code>: Return the score sum of the top <code>K</code> players.</li>
+	<li><code>reset(playerId)</code>: Reset the score of the player with the given id&nbsp;to 0 (in other words erase it from the leaderboard). It is guaranteed that the player was added to the leaderboard before calling this function.</li>
+</ol>
+
+<p>Initially, the leaderboard is empty.</p>
+
+<p>&nbsp;</p>
+<p><strong>Example 1:</strong></p>
+
+<pre><b>Input: </b>
+["Leaderboard","addScore","addScore","addScore","addScore","addScore","top","reset","reset","addScore","top"]
+[[],[1,73],[2,56],[3,39],[4,51],[5,4],[1],[1],[2],[2,51],[3]]
+<b>Output: </b>
+[null,null,null,null,null,null,73,null,null,null,141]
+
+<b>Explanation: </b>
+Leaderboard leaderboard = new Leaderboard ();
+leaderboard.addScore(1,73);   // leaderboard = [[1,73]];
+leaderboard.addScore(2,56);   // leaderboard = [[1,73],[2,56]];
+leaderboard.addScore(3,39);   // leaderboard = [[1,73],[2,56],[3,39]];
+leaderboard.addScore(4,51);   // leaderboard = [[1,73],[2,56],[3,39],[4,51]];
+leaderboard.addScore(5,4);    // leaderboard = [[1,73],[2,56],[3,39],[4,51],[5,4]];
+leaderboard.top(1);           // returns 73;
+leaderboard.reset(1);         // leaderboard = [[2,56],[3,39],[4,51],[5,4]];
+leaderboard.reset(2);         // leaderboard = [[3,39],[4,51],[5,4]];
+leaderboard.addScore(2,51);   // leaderboard = [[2,51],[3,39],[4,51],[5,4]];
+leaderboard.top(3);           // returns 141 = 51 + 51 + 39;
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= playerId, K &lt;= 10000</code></li>
+	<li>It's guaranteed that <code>K</code> is less than or equal to the current number of players.</li>
+	<li><code>1 &lt;= score&nbsp;&lt;= 100</code></li>
+	<li>There will be at most <code>1000</code>&nbsp;function calls.</li>
+</ul>
+
+
+**Companies**:  
+[Bloomberg](https://leetcode.com/company/bloomberg), [Google](https://leetcode.com/company/google), [Facebook](https://leetcode.com/company/facebook), [Twitter](https://leetcode.com/company/twitter)
+
+**Related Topics**:  
+[Hash Table](https://leetcode.com/tag/hash-table/), [Design](https://leetcode.com/tag/design/), [Sorting](https://leetcode.com/tag/sorting/)
+
+## Solution 1.
+
+```cpp
+// OJ: https://leetcode.com/problems/design-a-leaderboard/
+// Author: github.com/lzl124631x
+// Time:
+//      Leaderboard: O(1)
+//      addScore: O(1)
+//      top: O(NlogK)
+//      reset: O(1)
+// Space: O(N + K)
+class Leaderboard {
+    unordered_map<int, int> m;
+public:
+    Leaderboard() {}
+    void addScore(int playerId, int score) {
+        m[playerId] += score;
+    }
+    int top(int K) {
+        priority_queue<int, vector<int>, greater<>> pq;
+        for (auto &[id, score] : m) {
+            pq.push(score);
+            if (pq.size() > K) pq.pop();
+        }
+        int ans = 0;
+        while (pq.size()) {
+            ans += pq.top();
+            pq.pop();
+        }
+        return ans;
+    }
+    void reset(int playerId) {
+        m[playerId] = 0;
+    }
+};
+```