地址：http://acm.uestc.edu.cn/#/problem/show/1339

题目：

郭大侠与线上游戏

Time Limit: 6000/2000MS (Java/Others)     Memory Limit: 125535/65535KB (Java/Others)

#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <vector>
#include <cstdlib>
#include <string>

#define PI acos((double)-1)
#define E exp(double(1))
using namespace std;
set<int>p;
queue<int>q;
set<int>::iterator it,tit;
int main (void)
{
int t;
cin>>t;
while(t--)
{
int a,b;
scanf("%d",&a);
if(a==1)
{
scanf("%d",&b);
p.insert(b);
q.push(b);
if(p.size()==1)
{
it=p.begin();
continue;
}
if(b > (*it) && p.size()%2==0)
it++;
if (b < (*it) && p.size()%2!=0)
it--;
}
else if(a==2)
{
tit=p.find(q.front());
if(*tit > *it && p.size()%2==0)
it--;
else if(*tit < *it && p.size()%2!=0)
it++;
else if(*tit==*it && p.size()%2==0)
it--;
else if(*tit==*it && p.size()%2!=0)
it++;
q.pop();
p.erase(tit);
}
else
{
if(p.size()==1)
it=p.begin();
printf("%d\n",*it);
}
}
return 0;
}