【Pet HDU - 4707 】【利用并查集找深度】

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
const int maxn = 100000;
int T, N, D;
int x, y;
int f[maxn];
void init()
{
    for(int i = 0; i <= N - 1; i++)
        f[i] = i;
}
int Find(int root)
{
    while(root != f[root])
        root = f[root];
    return root;
}
int Solve(int x)
{
    int d = 0;
    while(x != f[x])
    {
        x = f[x];
        d++;
    }
    return d;
}
int main()
{
    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);
    scanf("%d", &T);
    while(T--)
    {
        scanf("%d %d", &N, &D);
        init();
        for(int i = 0; i < N - 1; i++)
        {
            scanf("%d %d", &x, &y);
            f[y] = x;
        }
        int ans = 0;
        for(int i = 0; i < N; i++)
        {
            if(Find(i) == 0)
            {
                if(Solve(i) > D)
                    ans++;
            }
        }
        printf("%d\n",ans);
    }
}