赛时调了不知道多久。。。

define int long long 和很大的数组大小是调试的时候加上去的

#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef long long ll;
const int N=1e6+5;
const ll mod=998244353; 
int n,x,y,p,q,r,step[N],f[N],lca[N][30],head[N],to[N<<1],ne[N<<1],tot=1;
ll w[N<<1],sum,E,dep[N];
vector<int> lf;
inline void add(int x,int y)
{
	ne[++tot]=head[x],head[x]=tot;
	to[tot]=y;
}
inline int find(int now,int fa)
{
	dep[now]=dep[fa]+1;
	if (now!=p && ne[head[now]]==0)lf.push_back(now);
	int ret=now;
	for (int i=head[now];i;i=ne[i])
	{
		if (to[i]==fa)continue;
		int v=find(to[i],now);
		f[to[i]]=i^1;
		if (dep[v]>dep[ret])ret=v;
	}
	return ret;
}
inline void dfs(int now,int fa)
{
	lca[now][0]=fa,step[now]=step[fa]+1;
	for (int i=1;(1<<i)<=n;i++)lca[now][i]=lca[lca[now][i-1]][i-1];
	for (int i=head[now];i;i=ne[i])
	{
		if (to[i]==fa)continue;
		dep[to[i]]=dep[now]+w[i];
		dfs(to[i],now);
	}
}
inline int LCA(int a,int b)
{
	if (a==b)return a;
	if (step[a]<step[b])swap(a,b);
	while (step[a]>step[b])a=lca[a][__lg(step[a]-step[b])];
	if (a==b)return a;
	for (int i=29;i>=0;i--)
	{
		if (lca[a][i]!=lca[b][i])a=lca[a][i],b=lca[b][i];
	}
	return lca[a][0];
}
inline ll dis(int a,int b)
{
	int l=LCA(a,b);
	return dep[a]+dep[b]-2*dep[l];
}
inline ll MOD(ll x)
{
	return (x%mod+mod)%mod;
}
inline ll pk(ll a,ll b)
{
	ll ret=1;
	while (b)
	{
		if (b&1)ret=ret*a%mod;
		b>>=1,a=a*a%mod;
	}
	return ret;
}
signed main()
{
	scanf("%lld",&n);
	for (int i=1;i<n;i++)scanf("%lld%lld",&x,&y),add(x,y),add(y,x);
	p=find(1,0);
	lf.clear();
	q=find(p,0);
	int pos=q,cnt=1;
	while (pos!=p)
	{
		w[f[pos]]=w[f[pos]^1]=1e9;
		pos=to[f[pos]],cnt++;
	}
	for (int i=0;i<lf.size();i++)
	{
		if (lf[i]!=q)
		{
			r=lf[i];break; 
		}
	}
	for (int i=2;i<=tot;i++)if (i!=f[r] && i!=(f[r]^1) && w[i]==0)w[i]=1;
	dep[p]=0,dfs(p,0);
	scanf("%lld",&E);
	E=(E*n)%mod;
	for (int i=1;i<=n;i++)
	{
		if (i==r)continue;
		(sum+=MOD(max(dis(i,p),dis(i,q))))%=mod;
	}
	if (r)
	{
		ll add=((E-sum)%mod+mod)%mod,nowd=MOD(max(dis(r,p),dis(r,q)));
		add=((add-nowd)%mod+mod)%mod;
		w[f[r]]=w[f[r]^1]=add;
	}
	else
	{
		ll tt=n/2+1;
		w[f[q]]=w[f[q]^1]=0;
		dep[p]=0,dfs(p,0);
		sum=0;
		for (int i=1;i<=n;i++)(sum+=MOD(max(dis(i,p),dis(i,q))))%=mod;
		ll add=((E-sum)%mod+mod)%mod;
		add=add*pk(tt,mod-2)%mod;
		w[f[q]]=w[f[q]^1]=add;
	}
	for (int i=2;i<=tot;i++)if (i%2==0)printf("%lld\n",w[i]);
	return 0;
}