A964.Delegation--Platinum

省选/NOI-

USACO

通过率:0%

时间限制:1.00s

内存限制:128MB

题目描述

Farmer John's farm consists of NN pastures (2N1052 \leq N \leq 10^5) connected
by N1N-1 roads, so that any pasture is reachable from any other pasture. That
is, the farm is a tree. But after 28 years of dealing with the tricky
algorithmic problems that inevitably arise from trees, FJ has decided that a
farm in the shape of a tree is just too complex. He believes that algorithmic
problems are simpler on paths.
Thus, his plan is to partition the set of roads into several paths, and
delegate responsibility for each path to a worthy farm hand. To avoid
contention, he wants each path to be the same length. He wonders for which
lengths there exists such a partition.
More precisely, for each 1KN11 \leq K \leq N-1, help Farmer John determine
whether the roads can be partitioned into paths of length exactly KK.

输入格式

  • In test cases 2-4 the tree forms a star; at most one vertex has degree greater than two.
  • Test cases 5-8 satisfy N103N\le 10^3.
  • Test cases 9-15 satisfy no additional constraints..

输出格式

The first line contains a single integer NN.
The next N1N-1 lines each contain two space-separated integers aa and bb
describing an edge between vertices aa and bb. Each of aa and bb is in the
range 1N1 \ldots N.

输入输出样例

  • 输入#1

    Output a bit string of length $N-1.$ For each $1\le K\le N-1,$ the $K$th bit
    of this string from the left should equal one if it is possible to partition
    the edges of the tree into paths of length exactly $K$ and $0$ otherwise.
    

    输出#1

    13
    1 2
    2 3
    2 4
    4 5
    2 6
    6 7
    6 8
    8 9
    9 10
    8 11
    11 12
    12 13
    

说明/提示

111000000000
It is possible to partition this tree into paths of length KK for K=1,2,3.K=1,2,3.

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