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), 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 <cstdio> #include <stdlib.h> typedef int EleType; const int maxn = 1e5; int MaxSize; struct SetType{ EleType Data; int Parent; } s[maxn]; void init(); void merge_Search(); void judge(int n, int m); void connect(int n, int m); int find_root(int child); void statistic(int maxsize); int main(){ init(); merge_Search(); statistic(MaxSize); } void init() { scanf("%d", &MaxSize); for (int i=0; i<MaxSize; i++) { s[i].Data = i + 1; s[i].Parent = -1; } } void merge_Search() { char c; int n, m; getchar(); scanf("%c", &c); while(c != 'S') { scanf(" %d %d", &n, &m); switch (c) { case 'C': judge(n, m); break; case 'I': connect(n, m); } getchar(); scanf("%c", &c); } } void judge(int n, int m) { if(find_root(n) == find_root(m)) printf("yes\n"); else printf("no\n"); } int find_root(int data) { int i = data - 1; if(s[i].Parent < 0) { return i; } s[i].Parent = find_root(s[i].Parent + 1); return s[i].Parent; } void connect(int n, int m) { int root1 = find_root(n); int root2 = find_root(m); if (root1 != root2) { if (s[root1].Parent > s[root2].Parent) { s[root2].Parent += s[root1].Parent; s[root1].Parent = root2; } else { s[root1].Parent += s[root2].Parent; s[root2].Parent = root1; } } } void statistic(int MAX) { int count = 0; for (int i=0; i<MAX; i++) { if(s[i].Parent < 0){ count++; } } if(count == 1) printf("The network is connected.\n"); else printf("There are %d components.\n", count); }