#P7746. [2019年杭电多校]Rikka with Travels
[2019年杭电多校]Rikka with Travels
Rikka with Travels
Problem Description
To enjoy their summer vacations, Rikka and Yuta decide to go travels. According to past experiences, contradictions always arose when they were planning for the same trip. This time, they decide to make plans dividually and will go travel twice. Coincidentally, they choose the same country Fantasy as the destination, which is a small island country on the Pacific. There are cities in Fantasy and they are connected with two-way roads. It is guaranteed that any two cities can reach each other by the road system. Though Rikka and Yuta love travels, visiting the same city more than once is still boring for them. Therefore, both Rikka and Yuta choose a simple path (i.e., a path without visiting any city more than once) as her/his plan. Moreover, they want to ensure the two paths do not intersect on any city. Suppose Rikka chooses the path from to , Yuta chooses the path from to (both and are allowed), they define the feature of the plan is an ordered pair , where represents the number of cities on the path from to . Now, Rikka wants to count the number of different features, i.e., the number of different integer pairs which satisfies there exists a valid travel plan meets . Since Rikka and Yuta are busy with planning their trip, Rikka asks you to help her calculate the answer.
Input
The first line of the input contains a single integer , the number of test cases. For each test case, the first line contains a single integer , the number of cities in Fantasy. Then lines follow. Each line contains two integers which represents a two-way road in the road system. The input guarantees that there are no more than test cases with .
Output
For each test case, output a single line with a single integer, the answer. Hint In the first test case, the possible features are . Therefore the answer is . In the second test case, the possible features are $(1,1),(1,2),(1,3),(1,4),(2,1),(2,2),(2,3),(3,1),(3,2), (4,1)$. Therefore the answer is .
Sample Input
2
4
1 2
1 3
1 4
5
1 2
2 3
3 4
3 5
Sample Output
5
10
Source
2019 Multi-University Training Contest 9