一.题目链接：

POJ-3784

二.题目大意：

给你 n 个数，当 i 为奇数时，输出中位数.

三.分析：

对顶堆维护即可.

另外不要 PE.

对顶堆学习

四.代码实现：

#include <set>
#include <map>
#include <ctime>
#include <queue>
#include <cmath>
#include <stack>
#include <bitset>
#include <vector>
#include <cstdio>
#include <sstream>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#define eps 1e-8
#define lc k * 2
#define rc k * 2 + 1
#define pi acos(-1.0)
#define ll long long int
using namespace std;

const int M = (int)1e6;
const ll mod = (ll)1e9 + 7;
const int inf = 0x3f3f3f3f;

priority_queue <int, vector<int>, less<int> > big;
priority_queue <int, vector<int>, greater<int> > small;

void init()
{
    while(!small.empty())
        small.pop();
    while(!big.empty())
        big.pop();
}

int main()
{
    int T;
    scanf("%d", &T);
    for(int ca = 1; ca <= T; ++ca)
    {
        init();
        int n;
        scanf("%*d %d", &n);
        printf("%d %d\n", ca, n / 2 + 1);
        int x;
        for(int i = 0; i < n; ++i)
        {
            scanf("%d", &x);
            if(i && !(i & 1))
            {
                if(i % 20 == 0)
                    printf("\n");
                else
                    printf(" ");
            }
            if(small.empty() || x > small.top())
                small.push(x);
            else
                big.push(x);
            if(small.size() > big.size() + 1)
            {
                big.push(small.top());
                small.pop();
            }
            if(big.size() >= small.size() + 1)
            {
                small.push(big.top());
                big.pop();
            }
            if(!(i & 1))
                printf("%d", small.top());
        }
        printf("\n");
    }
    return 0;
}