#include<bits/stdc++.h>
using namespace std;
const int N=1e5+10;
int a[N],cnt[N],st[N],n,m,ans;
vector<int>ve[N];
void dfs(int u,int t,int maxv)//t连续的1 maxv总路径中最长的连续的1
{
maxv=max(maxv,t+a[u]);
if(a[u]==0) cnt[u]=0;
else cnt[u]=t+a[u];
st[u]=1;
if(ve[u].size()==1&&maxv<=m&&u!=1) ans++;
//是叶子且不是1,且猫的数量<=m
for(int i=0;i<ve[u].size();i++)
{
int j=ve[u][i];
if(st[j]) continue;
dfs(j,cnt[u],maxv);
}
}
int main(void)
{
cin>>n>>m;
for(int i=1;i<=n;i++) cin>>a[i];
for(int i=1;i<=n-1;i++)
{
int a,b; cin>>a>>b;
ve[a].push_back(b);
ve[b].push_back(a);
}
dfs(1,0,0);
cout<<ans;
return 0;
}
C. Kefa and Park [Tree Traversal]
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Origin blog.csdn.net/qq_46527915/article/details/123596491
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