错一个点求助

#include<cstdio>
#include<vector>
#include<cstring>
#include<algorithm>
using namespace std;
const int N=330000;
int fa[N][22],w[N],n,m,dep[N],h[N],num;
int a1[N],c1[N],c2[N],ans[N];
struct node{
    int u,v,next;
}d[N*2];
vector<int> a2[N],a3[N],a4[N];
void add(int u,int v){
    d[num].u=u;
    d[num].v=v;
    d[num].next=h[u];
    h[u]=num++;

    d[num].u=v;
    d[num].v=u;
    d[num].next=h[v];
    h[v]=num++;
}
void dfs1(int u,int fath){
    dep[u]=dep[fath]+1;
    fa[u][0]=fath;

    for(int i=1;i<=20;++i)
        fa[u][i]=fa[fa[u][i-1]][i-1];

    for(int i=h[u];i!=-1;i=d[i].next)
        if(d[i].v!=fath)
            dfs1(d[i].v,u);
}
int lca(int u,int v){
    if(dep[u]<dep[v])
        swap(u,v);

    for(int i=20;i>=0;--i)
        if(dep[fa[u][i]]>=dep[v])
            u=fa[u][i];

    if(u==v)return u;

    for(int i=20;i>=0;--i)
        if(fa[u][i]!=fa[v][i]){
            u=fa[u][i];
            v=fa[v][i];
        }

    return fa[u][0];
}
void dfs(int u,int fath){
    int x1=c1[dep[u]+w[u]];
    int x2=c2[w[u]-dep[u]+n];

    for(int i=h[u];i!=-1;i=d[i].next)
        if(d[i].v!=fath)
            dfs(d[i].v,u);

    c1[dep[u]]+=a1[u];
    for(int i=0;i<a2[u].size();++i)
        c1[a2[u][i]]--;

    for(int i=0;i<a3[u].size();++i)
        c2[a3[u][i]]++;

    for(int i=0;i<a4[u].size();++i)
        c2[a4[u][i]]--;

    ans[u]+=c1[dep[u]+w[u]]-x1+c2[w[u]-dep[u]+n]-x2;
}
int main(){
//  freopen("P1600_13.in","r",stdin);
//  freopen("1.txt","w",stdout);

    scanf("%d%d",&n,&m);

    num=0;
    memset(h,-1,sizeof h);
    for(int i=1;i<n;++i){
        int u,v;
        scanf("%d%d",&u,&v);

        add(u,v);
    }

    dfs1(1,0);

    for(int i=1;i<=n;++i)
        scanf("%d",&w[i]);

    memset(a1,0,sizeof a1);
    for(int i=1;i<=m;++i){
        int s,t;
        scanf("%d%d",&s,&t);

        int p=lca(s,t);

        a1[s]++;
        a2[fa[p][0]].push_back(dep[s]);
        a3[t].push_back(dep[s]-2*dep[p]+n);
        a4[p].push_back(dep[s]-2*dep[p]+n);
    }

    dfs(1,0);

    for(int i=1;i<=n;++i)
        printf("%d ",ans[i]);

    return 0;
}

评测结果