Rt，这个题我的思路是：

先跑一遍p的最短路，再跑一遍q的最短路，最后每一条边统计它们的警告次数，以它们的警告次数为边权再建一个图，最后跑出来的最短路dis[n]受警告次数最少，输出它

但是我这个样例还没有过，有没有大佬帮我耐心看看qwq

虽然代码有一定的码量，但很多都是一样的

#include<bits/stdc++.h>
using namespace std;
const int N=1e4+5,M=5e4+5,INF=2147483647;
struct node{
	int from,to,dis,next;
}Edge[M];
struct Pair{
	int now,dis;
	bool operator <(const Pair &x)	const
	{
		return x.dis<dis;
	}
};
int disp[N],disq[N],disg[N],head[N],u[N],v[N],P[N],Q[N];
int n,m,tot;
bool vis[N];
inline int read()
{
	int x=0;
	bool w=0;
	char c=getchar();
	while(!isdigit(c))
		w|=c=='-',c=getchar();
	while(isdigit(c))
		x=(x<<1)+(x<<3)+(c^48),c=getchar();
	return w?-x:x;
}
inline void add(int u,int v,int w)
{
	Edge[++tot].to=v;
	Edge[tot].from=u;
	Edge[tot].dis=w;
	Edge[tot].next=head[u];
	head[u]=tot;
}
inline void Dijkstra_p()
{
	for(register int i=1;i<=n;++i)
		disp[i]=INF;
	memset(vis,0,sizeof(vis));
	priority_queue<Pair> q;
	q.push(Pair{1,0});
	while(!q.empty())
	{
		int u=q.top().now;q.pop();
		if(vis[u])	continue;
		vis[u]=1;
		for(register int i=head[u];i;i=Edge[i].next)
		{
			int v=Edge[i].to,w=Edge[i].dis;
			if(disp[u]+w<disp[v])
			{
				disp[v]=disp[u]+w;
				q.push(Pair{v,disp[v]});
			}
		}
	}
}
inline void Dijkstra_q()
{
	for(register int i=1;i<=n;++i)
		disq[i]=INF;
	memset(vis,0,sizeof(vis));
	priority_queue<Pair> q;
	q.push(Pair{1,0});
	while(!q.empty())
	{
		int u=q.top().now;q.pop();
		if(vis[u])	continue;
		vis[u]=1;
		for(register int i=head[u];i;i=Edge[i].next)
		{
			int v=Edge[i].to,w=Edge[i].dis;
			if(disq[u]+w<disq[v])
			{
				disq[v]=disq[u]+w;
				q.push(Pair{v,disq[v]});
			}
		}
	}
}
inline void Dijkstra_g()
{
	for(register int i=1;i<=n;++i)
		disg[i]=INF;
	memset(vis,0,sizeof(vis));
	priority_queue<Pair> q;
	q.push(Pair{1,0});
	while(!q.empty())
	{
		int u=q.top().now;q.pop();
		if(vis[u])	continue;
		vis[u]=1;
		for(register int i=head[u];i;i=Edge[i].next)
		{
			int v=Edge[i].to,w=Edge[i].dis;
			if(disg[u]+w<disg[v])
			{
				disg[v]=disg[u]+w;
				q.push(Pair{v,disg[v]});
			}
		}
	}
}
inline void Clear()
{
	memset(head,0,sizeof(head));
	memset(Edge,0,sizeof(Edge));
	tot=0;
}
signed main()
{
	n=read(),m=read();
	for(register int i=1;i<=m;++i)
	{
		u[i]=read(),v[i]=read();
		P[i]=read(),Q[i]=read();
	}
	for(register int i=1;i<=m;++i)
		add(u[i],v[i],P[i]);
	Dijkstra_p();
	Clear();
	for(register int i=1;i<=m;++i)
		add(u[i],v[i],Q[i]);
	Dijkstra_q();
	Clear();
	for(register int i=1;i<=m;++i)
	{
		int sum=0;
		if(disp[Edge[i].from]+P[i]!=disp[Edge[i].to])	++sum;
		if(disq[Edge[i].from]+Q[i]!=disq[Edge[i].to])	++sum;
		add(Edge[i].from,Edge[i].to,sum);
	}
	Dijkstra_g();
	printf("%d",disg[n]);
	return 0;
}