Network Connections UVA 793（并查集）

浏览数：41 / 时间：2015年06月09日

Network Connections

Time Limit: 3000ms Memory Limit: 131072KB

Network Connections

Bob, who is a network administrator, supervises a network of computers. He is keeping a log connections between the computers in the network. Each connection is bi-directional. Two computers are interconnected if they are directly connected or if they are interconnected with the same computer. Occasionally, Bob has to decide, quickly, whether two given computers are connected, directly or indirectly, according to the log information.

Write a program which based on information input from a text file counts the number of successful and the number of unsuccessful answers to the questions of the kind :

is computeri interconnected with computerj ?

Input and Output

The first line of the input contains the number of dataset, and it‘s followed by a blank line. Each dataset is defined as follows:

1.

The number of computers in the network (a strictly positive integer);

2.

A list of pairs of the form:

(a): c computeri computerj, where computeri and computerj are integers from 1 to . A pair of this form shows that computeri and computerj get interconnected.
(b): q computeri computerj, where computeri and computerj are integers from 1 to . A pair of this form stands for the question: is computeri interconnectedwith computerj?

There‘s a blank line between datasets.

Each pair is on a separate line. Pairs can appear in any order, regardless of their type. The log is updated after each pair of type (a) and each pair of type (b) is processed according to the current network configuration.

For example, the input file illustrated in the sample below corresponds to a network of 10 computers and 7 pairs. There are N1 successfully answered questions and N2 unsuccessfully answered questions. The program prints these two numbers to the standard output on the same line, in the order: successful answers, unsuccessful answers, as shown in the sample output. Print a blank line between datasets.

Sample Input

Sample Input

1,2

题目大意：

每次q后计算失败和成功的次数，最后输出成功的和失败的次数。

解题思路：

并查集，死了很多次在输入上面，输入还是需要一些技巧的。

代码：

#include<iostream>
#include<cstdio>
#include<string>
using namespace std;

const int maxn=1000000;//之前一直WA忘记了str0也可能随数字的增大而增长，

int t,n,parent[maxn],success,fail;
char str0[100];

void initial(){
    for(int i=0;i<=n;i++){parent[i]=i;}
    success=fail=0;
}

void outPut(){
    printf("%d,%d\n",success,fail);
    if(t) printf("\n");
}


int getRoot(int k){
    if(k!=parent[k]) parent[k]=getRoot(parent[k]);
    return parent[k];
}

void Union(int a,int b){
    parent[a]=b;
}

void solve(){
    int p,q,a,b;
    sscanf(str0+1,"%d%d",&a,&b);//从字符串里面截取数字的函数，以空格分数字.
    p=getRoot(a);
    q=getRoot(b);
    if(str0[0]=='c'){if(p!=q) Union(p,q);}
    if(str0[0]=='q'){
        if(p==q) success++;
        else fail++;
    }
}

int main(){
    scanf("%d",&t);
    while(t--){
        cin>>n;
        getchar();
        initial();
        while(gets(str0)){
            if(!str0[0]) break;//判断是否为空行
            solve();
        }
        outPut();
    }
    return 0;
}

郑重声明：本站内容如果来自互联网及其他传播媒体，其版权均属原媒体及文章作者所有。转载目的在于传递更多信息及用于网络分享，并不代表本站赞同其观点和对其真实性负责，也不构成任何其他建议。

Network Connections UVA 793（并查集）

标签： uvauva