有木有大神帮我看看，第一点总是TLE

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
const int N = 2005, M = 3005;

int T, n, m, to[M << 1], h[N], w[M << 1], ne[M << 1], idx;
int distances[N], updatecnt[N];
bool enter[N];

void add(int a, int b, int c) {
	to[idx] = b;
	ne[idx] = h[a];
	w[idx] = c;
	h[a] = idx++;
}

void init() {
	idx = 1;
	memset(h, -1, sizeof h);
	memset(distances, 0x3f3f3f3f, sizeof distances);
	memset(enter, false, sizeof enter);
	memset(updatecnt, 0, sizeof updatecnt);
}

bool spfa() {
	int queue[N * 10000];
	int l = 0, r = 0;
	distances[1] = 0;
	queue[r++] = 1;
	enter[1] = true;
	updatecnt[1]++;
	while (l < r) {
		int u = queue[l++];
		enter[u] = false;
		for (int ei = h[u]; ei != -1; ei = ne[ei]) {
			int v = to[ei];
			int c = w[ei];
			if (distances[u] + c < distances[v]) {
				distances[v] = distances[u] + c;
				if (!enter[v]) {
					if (++updatecnt[v] == n) {
						return true;
					}
					queue[r++] = v;
					enter[v] = true;
				} 
			}
		}
	}
	return false;
}

int main() {
    ios::sync_with_stdio(0);
    std::cin.tie(0);
    std::cout.tie(0);
    cin >> T;
    while (T--) {
    	cin >> n >> m;
    	init(); 
    	for (int i = 0; i < m; i++) {
    		int a, b, c;
    		cin >> a >> b >> c;
			if (c >= 0) {
				add(a, b, c);
				add(b, a, c);
			} 
			else {
				add(a, b, c);
			}
		}
		if (spfa()) {
			cout << "YES" << endl;
		}
		else {
			cout << "NO" << endl;
		}
	}
    return 0;
}