省赛1B题

http://acm.sdut.edu.cn/sdutoj/problem.php?action=showproblem&problemid=2159

set是集合，查找lower_bound，复杂度log₂(N)+1

http://www.cplusplus.com/reference/algorithm/lower_bound/

不必开数组，也开不开。

#include <iostream>
#include <set>
#include <string>

using namespace std;

typedef struct point
{
    int x,y;
} p;

bool operator <(const p a, const p b)
{
    if(a.x == b.x)
    {
        return a.y < b.y;
    }
    else return a.x < b.x;
}
int main()
{
    ios::sync_with_stdio(false);
    int n;
    int i = 0;
    while(cin>>n && n)
    {
        set<p> a;
        cout<<"Case "<<++i<<":"<<endl;
        while(n--)
        {
            string s;
            cin>>s;
            if(s == "add")
            {
                p temp;
                cin>>temp.x>>temp.y;
                a.insert(temp);
            }
            if(s == "find")
            {
                p temp;
                cin>>temp.x>>temp.y;
                int flag = 0;
                set<p>::iterator it = a.lower_bound(temp);
                for(; it != a.end(); ++it)
                {
                    if((*it).x > temp.x && (*it).y > temp.y)
                    {
                        cout<<(*it).x<<' '<<(*it).y<<endl;
                        flag = 1;
                        break;
                    }
                }
                if(flag == 0)
                {
                    cout<<-1<<endl;
                    continue;
                }
            }
            if(s == "remove")
            {
                p temp;
                cin>>temp.x>>temp.y;
                set<p>::iterator it = a.find(temp);
                a.erase(it);
            }
        }
        cout<<endl;
    }
}