Cow at Large
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Cornered at last, Bessie has gone to ground in a remote farm. The farm consists
of \(N\) barns (\(2 \leq N \leq 7 \cdot 10^4\)) and \(N-1\) bidirectional tunnels
between barns, so that there is a unique path between every pair of barns. Every
barn which has only one tunnel is an exit. When morning comes, Bessie will
surface at some barn and attempt to reach an exit.
But the moment Bessie surfaces at some barn, the law will be able to pinpoint
her location. Some farmers will then start at various exit barns, and attempt to
catch Bessie. The farmers move at the same speed as Bessie (so in each time
step, each farmer can move from one barn to an adjacent barn). The farmers know
where Bessie is at all times, and Bessie knows where the farmers are at all
times. The farmers catch Bessie if at any instant a farmer is in the same barn
as Bessie, or crossing the same tunnel as Bessie. Conversely, Bessie escapes if
she reaches an exit barn strictly before any farmers catch her.
Bessie is unsure at which barn she should surface. For each of the \(N\) barns,
help Bessie determine the minimum number of farmers who would be needed to catch
Bessie if she surfaced there, assuming that the farmers distribute themselves
optimally among the exit barns.
Note that the time limit for this problem is slightly larger than the default: 4 seconds for
C/C++/Pascal, and 8 seconds for Java/Python.
Problem credits: Dhruv Rohatgi
Problem credits: Dhruv Rohatgi
The first line of the input contains \(N\). Each of the following \(N-1\) lines
specify two integers, each in the range \(1 \ldots N\), describing a tunnel
between two barns.
Please output \(N\) lines, where the \(i\)th line of output tells the minimum number
of farmers necessary to catch Bessie if she surfaced at the \(i\)th barn.
atlarge.inatlarge.out7
1 2
1 3
3 4
3 5
4 6
5 73
1
3
3
3
1
1riseoj 작성
출처 올림피아드 > USACO > 2017-2018 > January > Platinum
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Cow at Large
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