upper_bound

upper_bound寻找第一个大于x的位置

#pragma GCC optimize(2)
#include <bits/stdc++.h>
using namespace std;

string id;
unordered_map<string, vector<int>> records;
vector<int> grade[4];  // A C M E
int main() {
    int n, m;
    cin >> n >> m;
    for(int i = 0; i < n; i ++) {
        int tmp[4] = {0};
        cin >> id;
        for(int j = 1; j < 4; j ++){
            cin >> tmp[j];
            tmp[0] += tmp[j];
        }
        tmp[0] = round(tmp[0] / 3.0);
        for(int j = 0; j < 4; j ++){
            grade[j].push_back(tmp[j]);
            records[id].push_back(tmp[j]);
        }
    }
    for(int i = 0; i < 4; i ++) sort(grade[i].begin(), grade[i].end());
    string names = "ACME";
    while(m --) {
        cin >> id;
        if(records.count(id) == 0) puts("N/A");
        else{
            int res = n + 1; char ch;
            for(int i = 0; i < 4; i ++) {
                int rank = 1 + n - (upper_bound(grade[i].begin(), grade[i].end(), records[id][i]) - grade[i].begin());
                if (rank < res) res = rank, ch = names[i];
            }
            cout << res << " " << ch << endl;
        }
    }
    return 0;
}

lower_bound做法

• 写一个cmp倒序排vector
  bool cmp(int a, int b) {return a > b;}
• 找rank时不用n -
• lower_bound()加入第4个参数greater<int>()