The kth great number

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65768/65768 K (Java/Others)
Total Submission(s): 16226    Accepted Submission(s): 6110

Problem Description Xiao Ming and Xiao Bao are playing a simple Numbers game. In a round Xiao Ming can choose to write down a number, or ask Xiao Bao what the kth great number is. Because the number written by Xiao Ming is too much, Xiao Bao is feeling giddy. Now, try to help Xiao Bao.  

 

Input There are several test cases. For each test case, the first line of input contains two positive integer n, k. Then n lines follow. If Xiao Ming choose to write down a number, there will be an " I" followed by a number that Xiao Ming will write down. If Xiao Ming choose to ask Xiao Bao, there will be a "Q", then you need to output the kth great number.   

 

Output The output consists of one integer representing the largest number of islands that all lie on one line.   

 

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

 

Sample Output 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).   题意：输入I表示插入一个数，输入Q表示要你求第k大的数   题解：用multiset，会自动排序，但是不会去重  

#include<iostream>
#include<algorithm>
#include<string.h>
#include<string>
#include<math.h>
#include<map>
#include<set>
#define ll long long
using namespace std;
multiset<ll>p;
string s,ss;
int n,k;
ll x;
int main()
{
    char c;
    while(cin>>n>>k)
    {
        p.clear();
        for(int i=0;i<n;i++)
        {
            cin>>c;
            if(c=='I')
            {
                cin>>x;
                p.insert(x);
                if(p.size()>k)
                    p.erase(p.begin());
            }
            else
            {
                multiset<ll>::iterator it;
                it=p.begin();
                cout<<*it<<endl;
            }
        }
    }
    return 0;

}