Ksyusha and Chinchilla solution codeforces
Ksyusha has a pet chinchilla, a tree on 𝑛� vertices and huge scissors. A tree is a connected graph without cycles. During a boring physics lesson Ksyusha thought about how to entertain her pet.
Chinchillas like to play with branches. A branch is a tree of 33 vertices.
The branch looks like this.Help Ksyusha choose the edges to be cut or tell that it is impossible.
The first line contains a single integer 𝑡� (1≤𝑡≤1041≤�≤104) — number of testcases.
The first line of each testcase contains a single integer 𝑛� (2≤𝑛≤2⋅1052≤�≤2⋅105) — the number of vertices in the tree.
The next 𝑛−1�−1 rows of each testcase contain integers 𝑣𝑖�� and 𝑢𝑖�� (1≤𝑣𝑖,𝑢𝑖≤𝑛1≤��,��≤�) — the numbers of vertices that the 𝑖�-th edge connects.
It is guaranteed that this set of edges forms a tree. It is also guaranteed that the sum of 𝑛� over all testcases does not exceed 2⋅1052⋅105.
Print the answer for each testcase.
If the desired way to cut the tree does not exist, print −1−1.
Otherwise, print an integer 𝑘� — the number of edges to be cut. In the next line, print 𝑘� different integers 𝑒𝑖�� (1≤𝑒𝑖<𝑛1≤��<�) — numbers of the edges to be cut. If 𝑘=0�=0, print an empty string instead.
If there are several solutions, you can print any.
Ksyusha and Chinchilla solution codeforces
2 2 8 -1 1 3 -1
-1 0 1 2 2 4 3
The first testcase in first test.