提交：https://codeforces.com/contest/1654/submission/165952111

/* name: CF1654D
 * author: 5ab
 * created at: 22-07-28 09:03
 */
#include <iostream>
#include <cstring>
using namespace std;

typedef long long ll;
const int max_n = 200000, max_p = 18000, max_a = 200000, mod = 998244353;

int hd[max_n], des[max_n<<1], nxt[max_n<<1], val[max_n], e_cnt;
int prm[max_p], lsp[max_a+1], inv[max_a+1]; bool isp[max_a+1];
int cur[max_p], mx[max_p], mn[max_p];
ll ans, tans;

void add(int s, int t, int v)
{
	des[e_cnt] = t, val[e_cnt] = v;
	nxt[e_cnt] = hd[s], hd[s] = e_cnt++;
}

inline void opcur(int x, int ratio)
{
	int tmp;
	while (x > 1)
	{
		tmp = lsp[x];
		x /= prm[tmp];
		cur[tmp] += ratio;
	}
}

inline void chmax(int& a, int b) { if (a < b) a = b; }
inline void chmin(int& a, int b) { if (a > b) a = b; }

void dfs1(int id, int fa)
{
	for (int p = hd[id], tmp, x; p != -1; p = nxt[p])
		if (des[p] != fa)
		{
			opcur(val[p], -1);
			opcur(val[p^1], 1);
			
			x = val[p];
			while (x > 1)
			{
				tmp = lsp[x];
				x /= prm[tmp];
				chmin(mn[tmp], cur[tmp]);
				chmax(mx[tmp], cur[tmp]);
			}
			x = val[p^1];
			while (x > 1)
			{
				tmp = lsp[x];
				x /= prm[tmp];
				chmin(mn[tmp], cur[tmp]);
				chmax(mx[tmp], cur[tmp]);
			}
			dfs1(des[p], id);
			
			opcur(val[p], 1);
			opcur(val[p^1], -1);
		}
}

void dfs2(int id, int fa)
{
	tans += ans;
	for (int p = hd[id]; p != -1; p = nxt[p])
		if (des[p] != fa)
		{
			ans = ans * inv[val[p]] % mod * val[p^1] % mod;
			dfs2(des[p], id);
			ans = ans * inv[val[p^1]] % mod * val[p] % mod;
		}
}

signed main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	
	int pc = 0;
	for (int i = 2; i <= max_a; i++)
	{
		if (!isp[i])
			prm[pc] = i, lsp[i] = pc++;
		for (int j = 0; j < pc && i * prm[j] <= max_a; j++)
		{
			isp[i*prm[j]] = true;
			lsp[i*prm[j]] = j;
			if (!(i % prm[j]))
				break;
		}
	}
	inv[1] = 1;
	for (int i = 2; i <= max_a; i++)
		inv[i] = 1ll * (mod - mod / i) * inv[mod%i] % mod;
	
	// cerr << pc << endl;
	
	int n, cas;
	
	cin >> cas;
	while (cas--)
	{
		memset(cur, 0, sizeof cur);
		memset(mx, 0, sizeof mx);
		memset(mn, 0, sizeof mn);
		
		cin >> n;
		memset(hd, -1, sizeof(int) * n), e_cnt = 0;
		
		for (int i = 1, u, v, x, y; i < n; i++)
		{
			cin >> u >> v >> x >> y, u--, v--;
			add(u, v, x), add(v, u, y);
		}
		dfs1(0, -1);
		
		ans = 1, tans = 0;
		for (int i = 0; i < pc; i++)
		{
			// if (mn[i] < 0 || mx[i] > 0)
			// 	cerr << prm[i] << "  " << mn[i] << " " << mx[i] << endl;
			for (int j = mn[i]; j < 0; j++)
				ans = (ans * prm[i]) % mod;
		}
		dfs2(0, -1);
		
		cout << tans % mod << endl;
	}
	
	return 0;
}

不懂啊，为什么会无缘无故 mle 呢？