Proving Equivalences Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 4263    Accepted Submission(s): 1510 Problem Description Consider the following exercise, found in a generic linear algebra t…

Consider the following exercise, found in a generic linear algebra textbook. Let A be an n × n matrix. Prove that the following statements are equivalent: 1. A is invertible. 2. Ax = b has exactly one solution for every n × 1 matrix b. 3. Ax = b is c…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=2767 题意:问最少加多少边可以让所有点都相互连通. 题解:如果强连通分量就1个直接输出0,否者输出入度为0的缩点,出度为0的缩点和的最大值 #include <iostream> #include <cstring> #include <cstdio> using namespace std; const int N = 2e4 + 10; const int M = 5e…

Road Construction Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 10141   Accepted: 5031 Description It's almost summer time, and that means that it's almost summer construction time! This year, the good people who are in charge of the r…

给出n个命题,m个推导,问最少添加多少条推导,能够使全部命题都能等价(两两都能互推) 既给出有向图,最少加多少边,使得原图变成强连通. 首先强连通缩点,对于新图,每一个点都至少要有一条出去的边和一条进来的边(这样才干保证它能到随意点和随意点都能到它) 所以求出新图中入度为0的个数,和出度为0的个数,加入的边就是从出度为0的指向入度为0的.这样还会有一点剩余,剩余的就乱连即可了. 所以仅仅要求出2者的最大值就OK. #include <iostream> #include<cstring&…

pid=2767">http://acm.hdu.edu.cn/showproblem.php?pid=2767 Proving Equivalences Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 2926    Accepted Submission(s): 1100 Problem Description Conside…

Redundant Paths Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 11047   Accepted: 4725 Description In order to get from one of the F (1 <= F <= 5,000) grazing fields (which are numbered 1..F) to another field, Bessie and the rest of the…

Network of Schools Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 13800   Accepted: 5504 Description A number of schools are connected to a computer network. Agreements have been developed among those schools: each school maintains a li…

Equivalent Sets Time Limit: 12000/4000 MS (Java/Others)    Memory Limit: 104857/104857 K (Java/Others)Total Submission(s): 3568    Accepted Submission(s): 1235 Problem Description To prove two sets A and B are equivalent, we can first prove A is a su…

Proving Equivalences Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 9296    Accepted Submission(s): 3281 Problem Description Consider the following exercise, found in a generic linear algebra t…