#P3439. [POI2006] MAG-Warehouse

[POI2006] MAG-Warehouse

题目描述

The streets of the New Byte City form a rectangular grid - those running east-west are simply called streets, while those running north-south are called avenues. To avoid mistakes, we shall call them h-streets and v-streets, respectively. The v-streets are numbered from 11 to 500 000 000500\ 000\ 000 eastwards. Similarly, the h-streets are numbered from 11 to 500 000 000500\ 000\ 000 northwards. Every v-street crosses every h-street and, conversely, every h-street crosses every v-street. The distance between two consecutive v-streets, as well as between two consecutive h-streets, is exactly one kilometre.

There are kk shops in the city, each one of them is situated at a crossroads. Byteasar, the merchant, supplies every single one of the kk shops, and furthermore he returns to some of them several times a day with fresh supplies. Recently he has decided to have a warehouse built, from which the goods would be delivered. For obvious reasons, it should stand at a crossroads. The lorry loaded with goods can supply only one shop per course - it leaves the warehouse, delivers to the shop and returns to the warehouse. The lorry always picks the shortest path from the warehouse to the shop, and the shortest one back (possibly the same one). The distance between points (xi,yi)(x_i, y_i) and (xj,yj)(x_j, y_j) equals max{xixj,yiyj}\max \{ |x_i - x_j|, |y_i - y_j| \}.

TaskWrite a programme that:

reads the locations of shops, as well as the numbers of their daily deliveries, from the standard inputdetermines such a warehouse's position that the summary distance of the lorry's daily route is minimal,writes the result to the standard output.

给定一个网格图,其上有一堆坏点(整点,同一位置多个),求一个整点,使得该整点到所有的坏点的切比雪夫距离之和最小。

求这个整点位置。(横纵坐标最大)

输入格式

The first line of the standard input contains one integer nn (1n100 0001 \le n \le 100\ 000), the number of shops in the New Byte City.

The following nn lines contain the shops' descriptions. The (i+1)(i+1)'th line contains three integers xix_i, yiy_i and tit_i (1xi,yi500 000 0001 \le x_i, y_i \le 500\ 000\ 000, 1ti1 000 0001 \le t_i \le 1\ 000\ 000), separated by single spaces. This triple means that the ii'th shop lies at the crossing of xix_i'th v-street and yiy_i'th h-street and the lorry delivers goods to this shop tit_i times a day.

输出格式

The first and only line of the standard output should contain two integers xmx_m and ymy_m, separated by a single space, denoting the optimal position of the warehouse as the crossroads of the xmx_m'th v-street and the ymy_m'th h-street. Should there be many optimal solutions, your programme is to pick one of them arbitrarily.

3
2 2 1
6 2 1
4 6 1
4 4

提示

感谢@oscar 提供SPJ