C++ :

#include <iostream>
#include <algorithm>
#include <cstring>

using namespace std;

typedef struct tagStudent
{
	short num;
	short marks;
} STU, *PSTU;

void InitData(PSTU& pStu, const short& nPeople);
int comp(const STU& stu1, const STU& stu2);
short CalcLimit(const PSTU& pStu, const short& nPeople, const short& nPlan);
void DisplayRes(const PSTU& pStu, const short nLimit);
void DestroyMem(PSTU& pStu);

int main()
{
	short nPeople = 0;
	short nPlan = 0;
	short nLimit = 0;
	PSTU pStu = NULL;
	
	cin >>nPeople >>nPlan;
	InitData(pStu, nPeople);
	sort(pStu, pStu + nPeople, comp);
	nLimit = CalcLimit(pStu, nPeople, nPlan);
	DisplayRes(pStu, nLimit);
	DestroyMem(pStu);
	return 0;
}

void InitData(PSTU& pStu, const short& nPeople)
{
	pStu = new STU[nPeople];
	memset(pStu, 0, nPeople*sizeof(STU));
	
	// 输入
	for (int i = 0; i < nPeople; ++i)
	{
		cin >>pStu[i].num >>pStu[i].marks;
	}
}

short CalcLimit(const PSTU& pStu, const short& nPeople, const short& nPlan)
{
	short people = (short)(nPlan * 1.5f);
	if (people >= nPeople)
	{
		return nPeople;
	}

	short marks = pStu[people-1].marks;
	short pos = people;
	while (pos < nPeople && pStu[pos].marks == marks) ++pos;
	return pos;
}

void DisplayRes(const PSTU& pStu, const short nLimit)
{
	cout <<pStu[nLimit-1].marks <<' ' <<nLimit <<endl;
	for (int i = 0; i < nLimit; ++i)
	{
		cout <<pStu[i].num <<' ' <<pStu[i].marks <<endl;
	}
}

void DestroyMem(PSTU& pStu)
{
	delete []pStu;
	pStu = NULL;
}

int comp(const STU& stu1, const STU& stu2)
{
	if (stu1.marks == stu2.marks)
	{
		return stu1.num <stu2.num;
	}
	return stu1.marks > stu2.marks;
}