P1068 [NOIP2009 普及组] 分数线划定

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#include <bits/stdc++.h>

using namespace std;
const int N = 5010;

struct Person {
    int k;
    int s;
} a[N];

bool cmp(const Person &a, const Person &b) {
    if (a.s == b.s) return a.k < b.k;
    return a.s > b.s;
}

int main() {
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= n; i++) cin >> a[i].k >> a[i].s;

    sort(a + 1, a + 1 + n, cmp);
    int c = m * 1.5;
    int cnt = 0;
    for (int i = c + 1; i <= n; i++) {
        if (a[i].s == a[c].s) cnt++;
        else break;
    }
    c += cnt;
    cout << a[c].s << " " << c << endl;
    for (int i = 1; i <= c; i++) cout << a[i].k << " " << a[i].s << endl;
    return 0;
}