NOIP '18 P3 - Constructing Tracks
View as PDFGiven a tree with  vertices. Edge 
 of the tree has length 
. We need to choose 
 edge-disjoint paths such that the length of the path with minimum length is maximized.
Input Specification
The first line contains two integers  and 
 denoting the number of vertices and the number of paths to be chosen.
In the following  lines, the 
 line contains three positive integers 
 denoting the 
 edge goes from 
 to 
 and has length 
.
Output Specification
The output contains an integer denoting the maximum possible minimum length of the  tracks chosen.
Sample Input 1
7 1
1 2 10
1 3 5
2 4 9
2 5 8
3 6 6
3 7 7
Sample Output 1
31
Note: the chosen path is the path from vertex 4 to vertex 7.
Sample Input 2
9 3
1 2 6
2 3 3
3 4 5
4 5 10
6 2 4
7 2 9
8 4 7
9 4 4
Sample Output 2
15
The chosen paths are the path from vertex 1 to vertex 7, vertex 6 to vertex 9, and vertex 8 to vertex 5.
Additional Samples
Additional samples can be found here.
Constraints
| Test Case | Degree of vertex  | ||||
|---|---|---|---|---|---|
| 1 | No | No | Yes | ||
| 2 | Yes | ||||
| 3 | Yes | No | No | ||
| 4 | No | Yes | |||
| 5 | Yes | No | |||
| 6 | No | ||||
| 7 | Yes | ||||
| 8 | |||||
| 9 | No | Yes | Yes | ||
| 10 | |||||
| 11 | |||||
| 12 | No | ||||
| 13 | |||||
| 14 | |||||
| 15 | |||||
| 16 | |||||
| 17 | No | ||||
| 18 | |||||
| 19 | |||||
| 20 | 
For all test cases, , 
, 
, 
.
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