# hdu 6073 Matching In Multiplication

Problem Description

In the mathematical discipline of graph theory, a bipartite graph is a graph whose vertices can be divided into two disjoint sets U and V (that is, U and V are each independent sets) such that every edge connects a vertex in U to one in V. Vertex sets U and V are usually called the parts of the graph. Equivalently, a bipartite graph is a graph that does not contain any odd-length cycles. A matching in a graph is a set of edges without common vertices. A perfect matching is a matching that each vertice is covered by an edge in the set.

Little Q misunderstands the definition of bipartite graph, he thinks the size of U is equal to the size of V, and for each vertex p in U, there are exactly two edges from p. Based on such weighted graph, he defines the weight of a perfect matching as the product of all the edges’ weight, and the weight of a graph is the sum of all the perfect matchings’ weight.

Please write a program to compute the weight of a weighted ”bipartite graph” made by Little Q.

Input

The first line of the input contains an integer T(1T15), denoting the number of test cases.

In each test case, there is an integer n(1n300000) in the first line, denoting the size of U. The vertex in U and V are labeled by 1,2,...,n.

For the next n lines, each line contains 4 integers vi,1,wi,1,vi,2,wi,2(1vi,jn,1wi,j109), denoting there is an edge between Ui and Vvi,1, weighted wi,1, and there is another edge between Ui and Vvi,2, weighted wi,2.

It is guaranteed that each graph has at least one perfect matchings, and there are at most one edge between every pair of vertex.

Output
For each test case, print a single line containing an integer, denoting the weight of the given graph. Since the answer may be very large, please print the answer modulo 998244353.

Sample Input
1
2
2 1 1 4
1 4 2 3

Sample Output
16

# “玲珑杯”ACM比赛 Round #18做题记录

A — 计算几何你瞎暴力

B — 数论你还会快速幂

C — 图论你先敲完模板

D — 最后你还是AK了

E — 数据结构你干瞪眼啊

（1）询问某个格子的值

（2） 询问某一行一段区间有多少种不同的值。

（3）某一行区间加一个数并且模256

（4）某一行区间翻转

# Codeforces Round #408 (Div. 2)做题记录

B. Find The Bone

C. Bank Hacking

D. Police Stations

E. Exam Cheating