3408. Barn Expansion

单点时限: 1.0 sec

内存限制: 256 MB

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.


  • 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 .


A single integer that is the number of barns that can be expanded.


0 2 2 7
3 5 5 8
4 2 6 4
6 1 8 6
0 0 8 1


Explanation of the sample:

There are barns. The first barn has its lower-left corner at and its upper-right corner at , and so on.

Only two barns can be expanded — the first two listed in the input. All other barns are each in contact with at least one other barn.

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8.9 EMB 奖励。

创建: 2 年,5 月前.

修改: 2 年,5 月前.

最后提交: 2 年,4 月前.

来源: USACO 2005 December Gold