hdu 1213

简单并查集

#include <cstdio>
#include <cstring>
#define maxn 30005
int fa[maxn],ans[maxn],n,m;

int findd( int x )
{
    return fa[x] == x ? x : fa[x] = findd(fa[x]);
}
int main()
{
	//freopen("d://in.txt", "r", stdin);
    int t;
    scanf("%d", &t);
    while(t--)
    {
        memset(ans, 0, sizeof(ans));
        scanf("%d%d", &n, &m);
        for (int i = 1; i <= n; ++i)
            fa[i] = i;
        for (int i = 0; i < m; ++i)
        {
            int x, y, u, v;
            scanf("%d%d", &u, &v);
            x = findd(u);
            y = findd(v);
            if (x != y)
                fa[x] = y;
        }
        for (int i = 1; i <= n; ++i)
            ans[findd(i)]++;
        int _max= 0;
        for (int i = 1; i <= n; ++i)
        {
        	if(ans[i])
        		_max++;
        }
        printf("%d\n", _max);
    }
    return 0;
}