PTA 7-15 File Transfer
2680 ワード
7-15 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≤104), 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:
where
where
where
Output Specification:
For each
Sample Input 1:
Sample Output 1:
Sample Input 2:
Sample Output 2:
簡単にセットを調べて、条件に従って出力するたびに、同じセットの中にいるかどうかを判断します.
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≤104), 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.簡単にセットを調べて、条件に従って出力するたびに、同じセットの中にいるかどうかを判断します.
#include
#include
using namespace std;
#define MAXN 10005
int par[MAXN],rank1[MAXN];
int n;
void init(int n)
{
for(int i=1;i<=n;i++)
{
par[i]=i;
rank1[i]=1;
}
}
int find(int x)
{
if(x==par[x])
{
return x;
}
return par[x]=find(par[x]);
}
void unite(int x,int y)
{
x=find(x);
y=find(y);
if(x==y)
{
return ;
}
if(rank1[x]>n;
init(n);
int sum=0;
while(cin>>c)
{
if(c=='S') break;
if(c=='I')
{
cin>>a>>b;
unite(a,b);
}
else if(c=='C')
{
cin>>a>>b;
if(same(a,b))
{
cout<1)
cout<