luogu3720 [AHOI2017初中组]guide[最短路]

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<algorithm>
 5 #include<cmath>
 6 #include<queue>
 7 #define dbg(x) cerr << #x << " = " << x <<endl
 8 using namespace std;
 9 typedef long long ll;
10 typedef double db;
11 typedef pair<int,int> pii;
12 typedef pair<ll,int> plli;
13 template<typename T>inline T _min(T A,T B){return A<B?A:B;}
14 template<typename T>inline T _max(T A,T B){return A>B?A:B;}
15 template<typename T>inline char MIN(T&A,T B){return A>B?(A=B,1):0;}
16 template<typename T>inline char MAX(T&A,T B){return A<B?(A=B,1):0;}
17 template<typename T>inline void _swap(T&A,T&B){A^=B^=A^=B;}
18 template<typename T>inline T read(T&x){
19     x=0;int f=0;char c;while(!isdigit(c=getchar()))if(c==‘-‘)f=1;
20     while(isdigit(c))x=x*10+(c&15),c=getchar();return f?x=-x:x;
21 }
22 const int N=1e5+7,M=5e5+7;
23 struct thxorz{int to,nxt,w1,w2;}G[M];
24 struct stothx{int u,v,w1,w2;}e[M];
25 int Head[N],tot;
26 int n,m;
27 inline void Addedge(int x,int y,int z1,int z2){
28     G[++tot].to=y,G[tot].nxt=Head[x],Head[x]=tot,G[tot].w1=z1,G[tot].w2=z2;
29 }
30 ll dis1[N],dis2[N];
31 priority_queue<plli,vector<plli>,greater<plli> > q;
32 #define y G[j].to
33 inline void dij1(int s){
34     memset(dis1,0x3f,sizeof dis1),q.push(make_pair(dis1[s]=0,s));
35     while(!q.empty()){
36         ll d=q.top().first;int x=q.top().second;q.pop();
37         if(dis1[x]^d)continue;
38         for(register int j=Head[x];j;j=G[j].nxt)if(d+G[j].w1<dis1[y])q.push(make_pair(dis1[y]=d+G[j].w1,y));
39     }
40 }
41 inline void dij2(int s){
42     memset(dis2,0x3f,sizeof dis2),q.push(make_pair(dis2[s]=0,s));
43     while(!q.empty()){
44         ll d=q.top().first;int x=q.top().second;q.pop();
45         if(dis2[x]^d)continue;
46         for(register int j=Head[x];j;j=G[j].nxt)if(d+G[j].w2<dis2[y])q.push(make_pair(dis2[y]=d+G[j].w2,y));
47     }
48 }
49 #undef y
50 int main(){//freopen("test.in","r",stdin);//freopen("test.ans","w",stdout);
51     read(n),read(m);
52     for(register int i=1;i<=m;++i)
53         read(e[i].u),read(e[i].v),read(e[i].w1),read(e[i].w2),Addedge(e[i].v,e[i].u,e[i].w1,e[i].w2);
54     dij1(n),dij2(n);
55     tot=0,memset(Head,0,sizeof Head);
56     for(register int i=1;i<=m;++i)
57         Addedge(e[i].u,e[i].v,(dis1[e[i].v]+e[i].w1!=dis1[e[i].u])+(dis2[e[i].v]+e[i].w2!=dis2[e[i].u]),0);
58     dij1(1);
59     return printf("%lld\n",dis1[n]),0;
60 }