MLE 4个点

#include <bits/stdc++.h>
using namespace std;
struct node
{
	int to, data;
};
struct node1
{
	int now, step;
};
const int N = 1500 + 10;
int n, m, x, u, v, w, ans, maxn = INT_MIN;
vector<node> a[N];
void bfs(int st)
{
	queue<node1> q;
	q.push({st, 0});
	while (!q.empty())
	{
		node1 f = q.front();
		// cout << f.now << " " << f.step << endl;
		// cout << q.size() << endl;
		q.pop();
		if (f.now == n)
		{
			maxn = max(maxn, f.step);
			continue;
		}
		for (int i = 0; i < a[f.now].size(); i++)
		{
			// vis[a[f.now][i].to] = 1;
			q.push({a[f.now][i].to, f.step + a[f.now][i].data});
		}
	}
	return;
}
int main()
{
	cin >> n >> m;
	for (int i = 1; i <= m; i++)
	{
		cin >> u >> v >> w;
		a[u].push_back({v, w});
	}
	bfs(1);
	if (maxn == INT_MIN)
	{
		cout << -1 << endl;
		return 0;
	}
	cout << maxn << endl;
	return 0;
}