暴力搜。。纯暴力。。
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <stack>
#include <queue>
#include <vector>
#include <algorithm>
#include <map>
#include <list>
#define ll long long
#define INF 0x3f3f3f3f
#define esp 1e-8
using namespace std;
bool mp[111][111],vis[111];
int k,n;
bool Bfs(int p)
{
int i,u,v,cnt;
memset(vis,0,sizeof(vis));
queue <int> q;
q.push(p);
vis[p] = 1;
cnt = 0;
while(!q.empty())
{
u = q.front();
q.pop();
for(i = 1; i <= n; ++i)
{
if(mp[u][i] && !vis[i])
{
cnt++;
q.push(i);
vis[i] = 1;
}
}
}
if(cnt == k) return 1;
return 0;
}
int main()
{
int i,u,v,cnt;
while(~scanf("%d %d",&n,&k))
{
cnt = 0;
memset(mp,0,sizeof(mp));
for(i = 0; i < n-1; ++i)
{
scanf("%d %d",&u,&v);
mp[u][v] = true;
}
for(i = 1; i <= n; ++i)
{
if(Bfs(i)) cnt++;
}
printf("%d\n",cnt);
}
return 0;
}