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??(), the total number of computers in a network. Each computer in the network is then represented by a positive integer between 1 and?. Then in the following lines, the input is given in the format:
|
1 |
I c1 c2 |
where?I?stands for inputting a connection between?c1?and?c2; or
|
1 |
C c1 c2 |
where?C?stands for checking if it is possible to transfer files between?c1?and?c2; or
|
1 |
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:
|
1 2 3 4 5 6 7 8 |
5 C 3 2 I 3 2 C 1 5 I 4 5 I 2 4 C 3 5 S |
Sample Output 1:
|
1 2 3 4 |
no no yes There are 2 components. |
Sample Input 2:
|
1 2 3 4 5 6 7 8 9 10 |
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:
|
1 2 3 4 5 |
no no yes yes The network is connected. |
测试代码：
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 |
// 梁笔记 // https://zouzhongliang.com #include<stdio.h> #include<stdlib.h> int S[10000]; int N; int Find(int S[],int i) { if(S[i] < 0) { return i; } else return S[i] = Find(S,S[i]); } void Check_connection(int S[]) { int root1,root2; int u, v; scanf("%d %d",&u,&v); root1 = Find(S,u-1); root2 = Find(S,v-1); if(root1 == root2) { printf("yes\n"); } else printf("no\n"); } void Union(int S[],int root1,int root2) { if(S[root2] < S[root1]) { S[root2] += S[root1]; S[root1] = root2; } else { S[root1] += S[root2]; S[root2] = root1; } } void Input_connection(int S[]) { int root1,root2; int u, v; scanf("%d %d",&u,&v); root1 = Find(S,u-1); root2 = Find(S,v-1); if(root1 != root2) { Union(S,root1,root2); } } void Initialization(int S[],int n) { for(int i=0;i<n;i++){ S[i] = -1; } } void Check_network(int S[],int n) { int i, counter=0; for(i=0;i<n;i++){ if(S[i]<0) counter++; } if(counter == 1) printf("The network is connected.\n"); else printf("There are %d components.\n", counter); } int main(void) { char in; scanf("%d",&N); Initialization(S,N); do { scanf("%s",&in); switch(in){ case 'C': Check_connection(S);break; case 'I': Input_connection(S);break; case 'S': Check_network(S,N);break; } } while(in != 'S'); return 0; } |
测试结果：
