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.
#include<stdio.h> #include<stdlib.h> #define MaxSize 100000 typedef int node; typedef struct Node { node *a; }Nodes,*qNode; typedef qNode QNode; //建树 void Create(QNode *q,int length) { *q = (Nodes*)malloc(sizeof(Nodes)); (*q)->a = (node*)malloc(sizeof(node)*(length+1)); for (int i = 0; i < length + 1; i++) { (*q)->a[i] = -1; } } //寻找集合 int Find(QNode q,int A) { while (q->a[A]>-1) { A = q->a[A]; } return A; } //判断是否在一个集合 void Look(QNode q, int A, int B) { if (Find(q, A) == Find(q, B)) { printf("yes\n"); } else { printf("no\n"); } } //建立连接 void Link(QNode *q, int A, int B) { A = Find(*q, A); B = Find(*q, B); int temp = 0; if (A != B) { if ((*q)->a[A] < (*q)->a[B]) { temp = (*q)->a[A] + (*q)->a[B]; (*q)->a[B] = A; (*q)->a[A] = temp; } else { temp= (*q)->a[B] + (*q)->a[A]; (*q)->a[A] = B; (*q)->a[B] = temp; } } } //查看是否全连通 void LookAll(QNode q,int length) { int flag = 0; for (int i = 1; i < length + 1; i++) { if (q->a[i] < 0) { flag++; } } if (flag == 1) { printf("The network is connected."); } else { printf("There are %d components.",flag); } } int main() { int n = 0; QNode q = NULL; scanf("%d\n", &n); Create(&q,n); int N = 1,A,B; char info; do{ scanf("%c", &info); switch (info) { case 'C': scanf("%d %d\n", &A, &B); Look(q, A, B); break; case 'I': scanf("%d %d\n", &A, &B); Link(&q, A, B); break; case 'S': LookAll(q, n); N = 0; break; default: break; } }while (N==1); return 0; }