莫名只有10分，求助

都快和题解一样了，不知道为什么WA

#include<iostream>
#include<cstdio>
#include<cstring>
#include<queue>
#include<algorithm>
using namespace std;
const int maxn=1010,maxm=2020,INF=2e9;
struct Edge{
	int u,v,c,f;
}edge[maxm];
struct Node{
	int u,d;
	bool operator<(const Node& n2)const{
		return d>n2.d;
	}
};
int first[maxn],next[maxm],tot,dis[maxn],vis[maxn],limit[maxm],cnt;
int n,m;
int ans=0;
void addedge(int u,int v,int c,int f){
	tot++;
	edge[tot].u=u;edge[tot].v=v;edge[tot].c=c;edge[tot].f=f;
	next[tot]=first[u];
	first[u]=tot;
}
void dijkstra(int start,int f){
	memset(vis,0,sizeof vis);
	for(int i=1;i<=n;i++){
		dis[i]=INF;
	}
	dis[start]=0;
	priority_queue<Node>q;
	q.push((Node){start,0});
	while(!q.empty()){
		Node crt=q.top();q.pop();
		if(vis[crt.u])continue;
		int u=crt.u;
		vis[u]=true; 
		for(int j=first[u];j;j=next[j]){
			int v=edge[j].v;
			if(vis[v])continue;
			if(edge[j].f < f)continue;
			if(dis[u]+edge[j].f < dis[v]){
				dis[v]=dis[u]+edge[j].f;
				q.push((Node){v,dis[v]});
			}
		}
	}
}
int main(){
	ios::sync_with_stdio(false);
	cin>>n>>m;
	for(int i=1;i<=m;i++){
		int u,v,c,f;
		cin>>u>>v>>c>>f;
		limit[i]=f;
		addedge(u,v,c,f);
		addedge(v,u,c,f);
	}
	sort(limit+1,limit+1+m,greater<int>());
	for(int i=1;i<=m;i++){
		dijkstra(1,limit[i]);
		if(dis[n] != INF){
			ans=max(ans,(int)((limit[i]*1e6)/dis[n]));
		}
	}
	cout<<ans;
	return 0;
}