1 人解决，1 人已尝试。
1 份提交通过，共有 1 份提交。
8.9 EMB 奖励。
单点时限: 1.0 sec
内存限制: 256 MB
Farmer John has $N$ ($1 \le N \le 25\,000$) rectangular barns on his farm, all with sides parallel to the $X$ and $Y$ axes and integer corner coordinates in the range $[0,10^6]$. 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.
A single integer that is the number of barns that can be expanded.
5 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 $5$ barns. The first barn has its lower-left corner at $(0,2)$ and its upper-right corner at $(2,7)$, 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.