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LeetCode 5097. 力扣排行榜

作者:互联网

地址 https://www.acwing.com/solution/LeetCode/content/5765/

题目描述
新一轮的「力扣杯」编程大赛即将启动,为了动态显示参赛者的得分数据,需要设计一个排行榜 Leaderboard。

请你帮忙来设计这个 Leaderboard 类,使得它有如下 3 个函数:

addScore(playerId, score):
假如参赛者已经在排行榜上,就给他的当前得分增加 score 点分值并更新排行。
假如该参赛者不在排行榜上,就把他添加到榜单上,并且将分数设置为 score。
top(K):返回前 K 名参赛者的 得分总和。
reset(playerId):将指定参赛者的成绩清零。题目保证在调用此函数前,该参赛者已有成绩,并且在榜单上。
请注意,在初始状态下,排行榜是空的

输入: 
["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]]
输出:
[null,null,null,null,null,null,73,null,null,null,141]

解释: 
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;

算法1
这道题目 我感觉更像系统设计题
由于需要依靠ID快速查找对应分数 并且分数还需要快速排序,所以我觉得应该 需要两个容器去进行存储,应对不同的需求。
查找当然是哈希,排序的话由于分数不是唯一的,我采取的是vector
那么对记录进行增删改的时候 就需要对两个容器进行操作

C++ 代码

 1 class Leaderboard {
 2 public:
 3     vector<int> scoreVec;
 4     map<int, int> idScore;
 5     Leaderboard() {
 6         scoreVec.clear();
 7         idScore.clear();
 8     }
 9 
10     void addScore(int playerId, int score) {
11         if (idScore.count(playerId) != 0) {
12             int oldscore = idScore[playerId];
13             idScore[playerId] += score;
14             vector<int>::iterator it = find(scoreVec.begin(), scoreVec.end(), oldscore);
15             *it += score;
16         }
17         else {
18             idScore[playerId] = score;
19             scoreVec.push_back(score);
20         }
21     }
22 
23     int top(int K) {
24         sort(scoreVec.begin(), scoreVec.end(),greater<int>());
25         int sum = 0;
26         for (int i = 0; i < scoreVec.size() && i < K; i++) {
27             sum += scoreVec[i];
28         }
29         return sum;
30     }
31 
32     void reset(int playerId) {
33         int score = idScore[playerId];
34         idScore.erase(playerId);
35         vector<int>::iterator it = find(scoreVec.begin(), scoreVec.end(), score);
36         scoreVec.erase(it);
37     }
38 };
View Code

 

标签:scoreVec,playerId,51,addScore,5097,力扣,score,LeetCode,leaderboard
来源: https://www.cnblogs.com/itdef/p/11785899.html