HDU4329

#include<cstdio>
#include<algorithm>
#include<map>
using namespace std;
int main()
{
    map<int ,int>mp;
    int n;
    while(~scanf("%d",&n)&&n)
    {
        int id,fg;
        mp[1000000000]=1;
        for(int i=0; i<n; i++)
        {
           scanf("%d %d",&id,&fg);
            mp[fg]=id;
            map<int ,int>::iterator it=mp.find(fg),it1;
            if(it==mp.begin())
                printf("%d %d\n",id,(++it)->second);
            else
            {
                it1=it;
                if(abs((--it)->first-fg)<=abs((++it1)->first-fg))
                    printf("%d %d\n",id,(it)->second);
                else
                  printf("%d %d\n",id,(it1)->second);

            }
        }
        mp.clear();

    }
    return 0;
}

map是有序的好处