1、待排序中的元素作数组的下标或map的键值

例题：PAT甲级_1141 PAT Ranking of Institutions

 

#include
     
      using namespace std;const int maxn = 100010;struct Node {    int personNum = 0;    int scoreB = 0, scoreA = 0, scoreT = 0;    int score;};map
      
        mp;vector
       
         ansSchoolName;bool cmp(string a, string b) {    if (mp[a].score != mp[b].score) return mp[a].score > mp[b].score;    else return mp[a].personNum < mp[b].personNum;} int main() {    int n;    scanf("%d", &n);    int score;    string id, schoolName;    for (int i = 0; i < n; i++) {        cin >> id >> score >> schoolName;        transform(schoolName.begin(), schoolName.end(), schoolName.begin(), ::tolower);        mp[schoolName].personNum++;        if (id[0] == 'A') mp[schoolName].scoreA += score;        else if (id[0] == 'B') mp[schoolName].scoreB += score;        else mp[schoolName].scoreT += score;    }    for (auto it = mp.begin(); it != mp.end(); it++) {        ansSchoolName.push_back(it->first);        it->second.score = (int)(it->second.scoreA + it->second.scoreB / 1.5 + it->second.scoreT*1.5);    }    sort(ansSchoolName.begin(), ansSchoolName.end(), cmp);    int r = 1;    printf("%d", ansSchoolName.size());    for (int i = 0; i < ansSchoolName.size(); i++) {        if (i > 0 && mp[ansSchoolName[i]].score != mp[ansSchoolName[i - 1]].score) {            r = i + 1;        }        printf("%d %s %d %d\n", r, ansSchoolName[i].c_str(), mp[ansSchoolName[i]].score, mp[ansSchoolName[i]].personNum);    }    return 0;}