题意  动态查询第K大的数

用小数在前优先队列维护K个数  每要插入一个数时 若这个数小于队首元素那么就不用插入了  否则队首元素出队  这个数入队  每次询问只用输出队首元素就行了

#include<cstdio>
#include<queue>
using namespace std;
int main()
{
    int n, a, k;
    char op[5];
    while(~scanf("%d%d", &n, &k))
    {
        priority_queue<int,vector<int>,greater<int> > pq;
        while(n--)
        {
            scanf("%s", op);
            if(op[0] == 'I')
            {
                scanf("%d",&a);
                if(pq.size()<k) pq.push(a);
                else if(a > pq.top()) pq.push(a),pq.pop();
            }
            else printf("%d\n", pq.top());
        }
    }
    return 0;
}

The kth great number

8 3
I 1
I 2
I 3
Q
I 5
Q
I 4
Q

1
2
3

Hint
Xiao  Ming  won‘t  ask  Xiao  Bao  the  kth  great  number  when  the  number  of  the  written number is smaller than k. (1=<k<=n<=1000000).
 

HDU 4006 The kth great number(优先队列·第K大数)

原文：http://blog.csdn.net/acvay/article/details/45040501