Hud 1213 How Many Tables[简单并查集]

/*
  Hud 1213 How Many Tables?
  简单并查集.
*/

#include<cstdio>
int father[1002],N,M;
void Init()
{
    for(int i=1;i<=N;i++)
    father[i]=i;
}
int Find_Father(int x)
{
    if(x!=father[x])
    father[x]=Find_Father(father[x]);
    return father[x];
}
void Union(int a,int b)
{
    int x=Find_Father(a);
    int y=Find_Father(b);
    if(x!=y) father[x]=y;
}
int main()
{
    int T;
    scanf("%d",&T);
    while(T--)
    {
        int a,b;
        scanf("%d%d",&N,&M);
        Init();
        for(int i=1;i<=M;i++)
        {
            scanf("%d%d",&a,&b);
            Union(a,b);
        }
        int UnionNum=0;
        for(int i=1;i<=N;i++)
        if(father[i]==i) UnionNum++;
        printf("%d\n",UnionNum);
    }
}