Hdu 4707 Pet -- 树形

#include<stdio.h>
#include<string.h>
#include<iostream>
#include<stdlib.h>
#include<vector>
using namespace std;
#define MAX 100000+3
vector<int>r[MAX];
bool vis[MAX];
int N,D,num;
void dfs(int x,int dis)
{
vis[x] = 1;
dis++;
int u;
for (int i = 0; i < r[x].size(); i++)
{
u = r[x][i];
if(!vis[u])
{
if(dis>D)num++;
dfs(u,dis);
}
}
}
int main()
{
int t;
int u,v;
cin>>t;
while(t--)
{
cin>>N>>D;
num = 0;
memset(vis,0,sizeof(vis));
for (int i = 0; i < N; i++)
{
r[i].clear();
}
for (int i = 0; i < N-1; i++)
{
cin>>u>>v;
r[u].push_back(v);
r[v].push_back(u);
}
dfs(0,0);
printf("%d\n",num);
}
return 0;
}