CSP-201712-4-行车路线

  1 #include<bits/stdc++.h>
  2 using namespace std;
  3 #define pii pair<int,int>
  4 #define mp make_pair
  5 #define inf 0x3f3f3f3f
  6 #define piii pair<int,pii>
  7 const int maxn=505;
  8 
  9 vector<pii>e1[maxn],e2[maxn];
 10 int dis1[maxn][maxn],dis2[maxn][maxn];
 11 int N,M;
 12 bool vis[maxn];
 13 int d[maxn];
 14 void dij(int s,vector<pii> (&e)[maxn]){//值传递会怎样
 15     memset(vis,0,sizeof(vis));
 16     memset(d,inf,sizeof(d));
 17     priority_queue<pii,vector<pii>,greater<pii> >q;
 18     q.push(mp(0,s));
 19     d[s]=0;
 20     while(!q.empty()){
 21         int u=q.top().second;q.pop();
 22         if(vis[u])continue;
 23         vis[u]=1;
 24         for(pii p:e[u]){
 25             int v=p.first,w=p.second;
 26             if(d[v]>d[u]+w){
 27                 d[v]=d[u]+w;
 28                 q.push(mp(d[v],v));
 29             }
 30         }
 31     }
 32 }
 33 int d2[maxn][2];
 34 bool vis2[maxn][2];
 35 void dij2(){
 36     memset(vis2,0,sizeof(vis2));
 37     memset(d2,inf,sizeof(d2));
 38     d2[1][0]=0;
 39     priority_queue<piii,vector<piii>,greater<piii> >q;
 40     q.push(mp(0,mp(1,0)));
 41     while(!q.empty()){
 42         piii o=q.top();q.pop();
 43         int u=o.second.first;
 44         int type=o.second.second;
 45         if(vis2[u][type])continue;
 46         vis2[u][type]=1;
 47         for(pii p:e1[u]){
 48             int v=p.first,w=p.second;
 49             if(w>=0){
 50                 if(d2[v][0]>d2[u][type]+w){
 51                     d2[v][0]=d2[u][type]+w;
 52                     q.push(mp(d2[v][0],mp(v,0)));
 53                 }
 54             }else if(type==0){
 55                 w*=-1;
 56                 if(d2[v][1]>d2[u][type]+w){
 57                     d2[v][1]=d2[u][type]+w;
 58                     q.push(mp(d2[v][1],mp(v,1)));
 59                 }
 60             }
 61         }
 62     }
 63 }
 64 void spfa(){}
 65 int main(){
 66     int a,b,c,t;
 67     ios::sync_with_stdio(false);
 68     cin>>N>>M;
 69     for(int i=1;i<=N;++i){
 70         for(int j=i;j<=N;++j){
 71             if(i==j)dis1[i][j]=dis2[i][j]=0;
 72             else{
 73                 dis1[i][j]=dis1[j][i]=inf;
 74                 dis2[i][j]=dis2[j][i]=inf;
 75             }
 76         }
 77     }
 78     while(M--){
 79         cin>>t>>a>>b>>c;
 80         if(t==0){
 81             e1[a].push_back(mp(b,c));
 82             e1[b].push_back(mp(a,c));
 83         }else if(t==1){
 84             if(dis2[a][b]>c)dis2[a][b]=dis2[b][a]=c;
 85             e2[a].push_back(mp(b,c));
 86             e2[b].push_back(mp(a,c));
 87         }
 88     }
 89     for(int i=1;i<=N;++i){
 90         dij(i,e2);
 91         for(int j=1;j<=N;++j){
 92             if(i!=j && d[j]!=inf && d[j]<=1005){
 93                 e1[i].push_back(mp(j,d[j]*d[j]*-1));
 94             }
 95         }
 96     }
 97     dij2();
 98     cout<<min(d2[N][0],d2[N][1])<<endl;
 99     return 0;
100 }