2015山东省第六届ACM省赛 Lowest Unique Price

题意：查找只被竞价一次的价格中的最小值。

set用法:

http://www.cnblogs.com/BeyondAnyTime/archive/2012/08/13/2636375.html

#include <iostream>
#include <string>
#include <map>
#include <set>
#include <stdio.h>

using namespace std;

int main()
{
    set<int> myset;
    map<int,int> mymap;
    char c;
    int T,n,x;
    scanf("%d",&T);
    while(T--)
    {
        myset.clear();
        mymap.clear();

        scanf("%d",&n);

        for(int i=0; i<n; i++)
        {
            scanf(" %c",&c);//空格忽略\n
            if(c=='b')
            {
                scanf("%d",&x);
                myset.insert(x);
                mymap[x]++;
                if(mymap[x]>1)
                    myset.erase(x);
            }
            else if(c=='c')
            {
                scanf("%d",&x);
                mymap[x]--;
                if(mymap[x]==1)
                    myset.insert(x);
                else if(mymap[x]==0)
                    myset.erase(x);
            }
            else
            {
                if(!myset.empty())
                    printf("%d\n",*myset.begin());
                else
                    printf("none\n");
            }
        }

    }
    return 0;
}