Codeforces Round 748 (Div. 3)---E. Gardener and Tree---深搜变种+贪心+数据结构---1600

#include <bits/stdc++.h>
#define pb push_back
#define YES cout<<"YES"<<'\n';
#define NO cout<<"NO"<<'\n';
using namespace std;
using ll = long long;
void solve()
{
	ll n,k;cin>>n>>k;
	queue<ll>e;
	vector<ll>q[n+10],dep(n+10),vis(n+10),j(n+10);
	ll x,y;
	for(ll i=1;i<n;i++)
	{
		cin>>x>>y;
		q[x].push_back(y);
		q[y].push_back(x);
		vis[x]++;
		vis[y]++;
	}
	for(ll i=1;i<=n;i++)
	{
		if(vis[i]==1) //最外边
		{
			e.push(i);
			j[i]++;
			dep[i]=1;
		}
	}
	while(e.size())
	{
		ll x=e.front();
		e.pop();
		for(auto ed:q[x])
		{
			if(vis[ed]==1) continue;//最外边
			dep[ed]=dep[x]+1;
			if(--vis[ed]==1) e.push(ed);//最后一次入队
		}
	}
	ll ans=0;
	for(ll i=1;i<=n;i++)
	{
		if(dep[i]<=k) ans++;
	}
	cout<<n-ans<<'\n';
}
int main()
{
	cin.tie(0);
	cout.tie(0);
	ios_base::sync_with_stdio( false );
	
	ll t;cin>>t;
	while( t-- ) solve();
	return 0;
}