05-树8 File Transfer (25 分)

05-树8 File Transfer (25 分)

We have a network of computers and a list of bi-directional connections. Each of these connections allows a file transfer from one computer to another. Is it possible to send a file from any computer on the network to any other?

Input Specification:

Each input file contains one test case. For each test case, the first line contains N (2≤N≤10​4​​), the total number of computers in a network. Each computer in the network is then represented by a positive integer between 1 and N. Then in the following lines, the input is given in the format:

I c1 c2  

where I stands for inputting a connection between c1 and c2; or

C c1 c2    

where C stands for checking if it is possible to transfer files between c1 and c2; or

S

where S stands for stopping this case.

Output Specification:

For each C case, print in one line the word "yes" or "no" if it is possible or impossible to transfer files between c1 and c2, respectively. At the end of each case, print in one line "The network is connected." if there is a path between any pair of computers; or "There are k components." where k is the number of connected components in this network.

Sample Input 1:

5
C 3 2
I 3 2
C 1 5
I 4 5
I 2 4
C 3 5
S

Sample Output 1:

no
no
yes
There are 2 components.

Sample Input 2:

5
C 3 2
I 3 2
C 1 5
I 4 5
I 2 4
C 3 5
I 1 3
C 1 5
S

Sample Output 2:

 

no
no
yes
yes
The network is connected.

 

题解思路；简单的并查集，用数组存电脑的编号但是是错位的，比如数组0 存1号机，注意这个错位就行了

#include
#include
using namespace std;
int N;
int Find(int* S,int X)
{
	if(S[X]<0)	return X;
	else	return S[X]=Find(S,S[X]);//路径压缩，通过不断地压缩路径，让树越来越扁 */
}
void Union(int* S,int X1,int X2)
{
	int root1=Find(S,X1-1);
	int root2=Find(S,X2-1);
	if(root1==root2)
	{
		S[root2]=root1;
		root1-=root2;
	}
	else
	{
		//按秩归并 
		if(root1>x1>>x2;
	Union(S,x1,x2);
}
void Check_connection(int* S)
{
	int x1,x2;
	cin>>x1>>x2;
	int root1,root2;
	root1=Find(S,x1-1);
	root2=Find(S,x2-1);
	if(root1==root2)
		cout<<"yes"<>N;
	int S[N];
	for(int i=0;i>c;
		switch(c)
		{
			case 'C':	Check_connection(S);break;
			case 'S':	Check_network(S,N);break; 
			case 'I':	Input_connection(S);break;
		}
	}while(c!='S');
	return 0;
}