Number of connected components (connected component _ and query set)

Number of connected components of zookeeper Crawling in process... Crawling failed Time limit:1000 ms Memory limit:65536kb 64bit Io format:% LLD & % llusubmitstatus

Description

In an undirected graph, if a path exists between the vertex VI and the vertex VJ, the VI is connected to the VJ. If any two vertices in the graph are connected, the graph is called a connected graph. Otherwise, the graph is called a non-connected graph. The connected subgraph is called a connected component, in this case, the number of vertices contained in a subgraph is very large. For example, an undirected graph has five vertices, 1-3-5 is connected, 2 is connected, and 4 is connected. Then the undirected graph has three connected components.

Input

The first line is an integer T, indicating that there are T group test samples (0 <t <= 50 ). The start line of each test sample contains two integers n, m, (0 <n <= 20, 0 <= m <= 200) representing n vertices and m edges respectively. The following m rows have two integers U, V, and vertex u connected to vertex v.

Output

Each line has an integer that represents the number of connected components.

Sample Input

23 11 23 23 21 2

Sample output

21

Hint

Check the set question and check the set at http://blog.csdn.net/u013486414/article/details/38682057;

#include <stdio.h>#include <string.h>#include <stdlib.h>int uset[10010];int rank[10010];int s[10010];void makeset(int n){    memset(uset,0,sizeof(uset));    for(int i=0;i<n;i++)        uset[i]=i;}int find(int x){    if(x!=uset[x])        uset[x]=find(uset[x]);    return uset[x];}void unionset(int x,int y){    if((x=find(x))==(y=find(y)))        return ;    if(rank[x]>rank[y])        uset[y]=x;    else    {        uset[x]=y;        if(rank[x]==rank[y])            rank[y]++;    }}int main(){    int T;    int n,m,i;    int a,b;    int f;    int sum=0;    scanf("%d",&T);    while(T--)    {        scanf("%d %d",&n,&m);        memset(s,0,sizeof(s));        makeset(n);        while(m--)        {            scanf("%d %d",&a,&b);            unionset(a,b);        }        for(i=0;i<n;i++)        {            f=find(i);            s[f]++;        }        sum=0;        for(i=0;i<n;i++)        {            if(s[i])                sum++;        }         printf("%d\n",sum);    }    return 0;}

Number of connected components (connected component _ and query set)