bzoj#P1730. [Usaco2005 dec]Barn Expansion 牛棚扩张
[Usaco2005 dec]Barn Expansion 牛棚扩张
题目描述
Farmer John has rectangular barns on his farm, all with sides parallel to the and axes and integer corner coordinates in the range . These barns do not overlap although they may share corners and/or sides with other barns. Since he has extra cows to milk this year, FJ would like to expand some of his barns. A barn has room to expand if it does not share a corner or a wall with any other barn. That is, FJ can expand a barn if all four of its walls can be pushed outward by at least some amount without bumping into another barn. If two barns meet at a corner, neither barn can expand. Please determine how many barns have room to expand.
约翰有 个矩形牛棚,它们的墙均与坐标轴平行,而且其坐标在 范围内。任意两个牛棚不重叠,但可能会有公共的墙。由于约翰的奶牛持续增加,他不得不考虑扩张牛棚。一个牛棚可以扩张,当且仅当它的四边均不与其它牛棚接触。如果两个牛棚有一个公共角,那它们均是不可扩张的。统计有多少牛棚可以扩张。
输入格式
- Line :A single integer,.
- Lines :Four space-separated integers , and , describing one barn. The lower-left corner of the barn is at and the upper right corner is at .
第一行输入 ,之后 行每行输入一个牛棚的左下角和右上角坐标。
输出格式
- Line :A single integer that is the number of barns that can be expanded.
输出可扩张的牛棚数。
5
0 2 2 7
3 5 5 8
4 2 6 4
6 1 8 6
0 0 8 1
2
样例说明
INPUT DETAILS:
There are 5 barns. The first barn has its lower-left corner at and its upper-right corner at , and so on.
仅有前两个牛棚可以扩张。
数据规模与约定
对于 的数据,。
题目来源
Gold