这道题可以用Dijkstra算法+贪心做吗？时间复杂度：2*log(m)*m

#include<bits/stdc++.h>
using namespace std;
long long n, m, u[25005], cnt, dist1, v[25005], ans, w[25005], dist[255], fk[255], vis[255], b[255][255];
vector<pair<int, int>> a[3000];
void mjl(){
	memset(dist, 0x3f3f3f3f, sizeof dist);
	memset(vis, 0, sizeof vis);
	memset(fk, 0, sizeof fk);
	priority_queue<pair<long long, int>, vector<pair<long long, int>>, greater<pair<long long, int>>> x;
	dist[1]=0;
	x.push({0, 1});
	while(!x.empty()){
		auto t=x.top();
		x.pop();
		int ty=t.second;
		if(vis[ty]) continue;
		vis[ty]=1;
		for(auto i:a[ty]){
			if(dist[i.second]>dist[ty]+i.first){
				dist[i.second]=dist[ty]+i.first;
				fk[i.second]=ty;
				x.push({dist[i.second], i.second});
			}
		}
	}
}
int main(){ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin>>n>>m;
	for(int i=1;i<=m;i++){
		cin>>u[i]>>v[i]>>w[i];
		b[u[i]][v[i]]=i;
		b[v[i]][u[i]]=i;
		a[u[i]].push_back({w[i], v[i]});
		a[v[i]].push_back({w[i], u[i]});
	}
	mjl();
	dist1=dist[n];
	int l=n;
	while(l!=0){
		if(ans<w[b[l][fk[l]]]){
			cnt=b[l][fk[l]];
			ans=w[b[l][fk[l]]];
		}
		l=fk[l];
	}
	for(int i=1;i<=n;i++){
		a[i].clear();
	}
	for(int i=1;i<=m;i++){
		if(cnt==i){
			w[i]*=2;
		}
		a[u[i]].push_back({w[i], v[i]});
		a[v[i]].push_back({w[i], u[i]});
	}
	mjl();
	int l1=n;
	while(l1!=0){
		l1=fk[l1];
	}
	if(dist1+ans>=dist[n]){
		cout<<dist[n]-dist1;
	}else{
		cout<<ans;
	}
	return 0;
}