原题链接:
https://leetcode.cn/problems/reward-top-k-students/

比较适合用于练习 语言基础语法的一道题

解法1:

模拟

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/*
    模拟
    哈希表记录feed_back的分数 然后遍历report直接计算分数
*/
class Solution {
public:
    vector<int> topStudents(vector<string>& positive_feedback, vector<string>& negative_feedback, vector<string>& report, vector<int>& student_id, int k) {
        unordered_map<string,int>score;
        for(int i = 0; i < positive_feedback.size() ; i++ ){
            score[positive_feedback[i]] = 3;
        }

        for(int i = 0; i < negative_feedback.size(); i++){
            score[negative_feedback[i]] = -1;
        }

       
        vector<int>s(report.size(),0);

        for(int i = 0 ; i < report.size() ; i++){
            int m = report[i].size();
            // cout << report[i] << endl;
            for(int j = 0; j < m ; ){
                int k = j + 1;
            
                while(k < m && report[i][k] != ' ' ){
                    k++;
                }
                // cout << report[i].substr(j,k - j) << endl;
                // c++ unordered_map 不存在键值 直接默认值为0
                s[i] += score[report[i].substr(j,k - j)];
                j = k + 1;
            }
        }

        vector<pair<int,int>>p(report.size());

        for(int i = 0 ; i < report.size() ; i++){
            p[i].first = s[i];
            p[i].second = student_id[i];
        }

        sort(p.begin(),p.end(),[&](pair<int,int>a,pair<int,int>b)->bool{
            if(a.first == b.first){
                return a.second < b.second;
            }else{
                return a.first > b.first;
            }
        });
        
        vector<int>ans;

        for(int i = 0 ; i < k ; i++){
            ans.push_back(p[i].second);
        }

        return ans;
    }
};