In some countries building highways takes a lot of time... Maybe that's because there are many possiblities to construct a network of highways and engineers can't make up their minds which one to choose. Suppose we have a list of cities that can be c…

https://blog.csdn.net/zhaoruixiang1111/article/details/79185927 为了学一个矩阵树定理 从行列式开始学(就当提前学线代了.. 论文生成树的计数及其应用 矩阵数定理: 截图来自于上述论文 裸题. #include<cstdio> #include<cstdlib> #include<cstring> #include<iostream> using namespace std; ; ; double…

更正了我之前打错的地方,有边的话G[i][j]=-1; WA了好多次,中间要转成long double才行..这个晚点更新. #include<cstdio> #include<cstdlib> #include<cstring> #include<iostream> using namespace std; typedef long double ld; ; ; int map[N][N]; ld G[N][N]; ld myabs(ld x){ ? x:…

传送门 矩阵树定理模板题. 题意简述:自己看题面吧太简单懒得写了 直接构建出这4n4n4n个点然后按照题面连边之后跑矩阵树即可. 代码: #include<bits/stdc++.h> #define ri register int #define idx(x) ((x)%n) using namespace std; const int N=505,mod=2007; int n,a[N][N]; inline void add(int u,int v){++a[u][u],++a[v][v…

http://www.lydsy.com/JudgeOnline/problem.php?id=2467 题意: 思路:要用矩阵树定理不难,但是这里的话需要取模,所以是需要计算逆元的,但是用辗转相减会更简单. 引用一大神博客里的介绍:http://blog.csdn.net/u013010295/article/details/47451451 值得一提的是,有些题目要求行列式模上一个数的结果.怎么求模意义下的行列式呢?这些题答案都比较大,用浮点数的话精度达不到要求,确实是一个问题.(显然强行用…

题目大意: 求最小生成树的数量 曾今的我感觉这题十分的不可做 然而今天看了看,好像是个类模板的题.... 我们十分容易知道,记能出现在最小生成树中的边的集合为\(S\) 那么,只要是\(S\)中的边构成的树,一定能构成最小生成树 我们只要预处理哪些可能在最小生成树中即可 打个树剖维护以下就可以了 太懒了,不想打太长,然后就拿并查集随便弄了弄 最后来个矩阵树就行了 \(31011\)不是一个质数,用辗转相除法来消元 复杂度\(O(n^3 \log n)\) #include <cstdio> #…

SPOJ104 Highways Description In some countries building highways takes a lot of time- Maybe that's because there are many possiblities to construct a network of highways and engineers can't make up their minds which one to choose. Suppose we have a l…

目录 @0 - 参考资料@ @0.5 - 你所需要了解的线性代数知识@ @1 - 矩阵树定理主体@ @证明 part - 1@ @证明 part - 2@ @证明 part - 3@ @证明 part - 4@ @2 - 一些简单的推广@ @3 - 例题与应用@ @4 - prüfer 序列@ @0 - 参考资料@ MoebiusMeow 的讲解(超喜欢这个博主的!) 网上找的另外一篇讲解 @0.5 - 你所需要了解的线性代数知识@ 什么是矩阵? 什么是高斯消元?这个虽然与主题无关,但是求解行列…

欲学矩阵树定理必先自宫学习一些行列式的姿势 然后做一道例题 #include <iostream> #include <cstring> #include <cstdio> #include <cmath> using namespace std; typedef long long ll; int T, n, m, uu, vv; double w[15][15]; const double eps=1e-7; void gauss(){ n--; for…

题目: In some countries building highways takes a lot of time... Maybe that's because there are many possiblities to construct a network of highways and engineers can't make up their minds which one to choose. Suppose we have a list of cities that can…