并查集模板

/*并查集 */
#include <cstdio>
#include <cstring>
#include <algorithm>
#define N 100010
#define INF 0x3f3f3f3f
int father[N],a[N];
int find(int x)
{
        return x==father[x]?x:(father[x]=find(father[x]));
}
int main()
{
        int t,i,j,n;
        scanf("%d",&t);
        while(t--)
        {
                scanf("%d",&n);
                int u,v,w,b,c;
                memset(a,0,sizeof(a));
                for(i=0; i<=n; i++)
                        father[i]=i;
                for(i=1; i<n; i++)
                {
                        scanf("%d%d%d",&u,&v,&w);
                        if(w)
                                continue;
                        b=find(u);
                        c=find(v);
                        if(b!=c)
                                father[b]=c;
                }
                for(i=1; i<=n; i++)
                        b=find(i);
                for(i=1; i<=n; i++)/*   该集合有多少个人    */
                        a[father[i]]++;
                int sum=0;
                for(i=1; i<=n; i++)
                        if(a[i]%2)
                                sum^=a[i];
                printf("%d\n",sum);
        }
        return 0;
}