解释+答案！

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
int n, m;
cin >> n >> m;

vector<pair<int, int>> candidates; // {报名号, 成绩}
for (int i = 0; i < n; i++) {
    int id, score;
    cin >> id >> score;
    candidates.push_back({id, score});
}

// 排序：成绩降序，成绩相同按报名号升序
sort(candidates.begin(), candidates.end(), [](const auto& a, const auto& b) {
    if (a.second != b.second) 
        return a.second > b.second;
    return a.first < b.first;
});

// 计算面试分数线
int interview_count = static_cast<int>(m * 1.5);
int score_line = candidates[interview_count - 1].second;

// 统计实际进入面试的选手
int actual_count = 0;
for (const auto& candidate : candidates) {
    if (candidate.second >= score_line) {
        actual_count++;
    } else {
        break; // 已排序，后续成绩更小
    }
}

// 输出结果
cout << score_line << " " << actual_count << endl;
for (int i = 0; i < actual_count; i++) {
    cout << candidates[i].first << " " << candidates[i].second << endl;
}

return 0;

}