[网络流24题] 汽车加油行驶问题

 1     #include<iostream>
 2     #include<cstdio>
 3     #include<cstring>
 4     #include<algorithm>
 5     #define inf 1000000000
 6     using namespace std;
 7     inline int read(){
 8         int re=0,flag=1;char ch=getchar();
 9         while(ch>‘9‘||ch<‘0‘){
10             if(ch==‘-‘) flag=-1;
11             ch=getchar();
12         }
13         while(ch>=‘0‘&&ch<=‘9‘) re=(re<<1)+(re<<3)+ch-‘0‘,ch=getchar();
14         return re*flag;
15     }
16     const int dx[5]={0,-1,0,1,0},dy[5]={0,0,-1,0,1};
17     int n,m,k1,k2,k3,a[110][110];
18     int dis[110][110][20];bool vis[110][110][20];
19     struct que{
20         int x,y,z;
21         que(){}
22         que(int xx,int yy,int zz){x=xx;y=yy;z=zz;}
23     };
24     que q[1000010];
25     void spfa(){
26         int i,j,k,x,y,z,tx,ty,tz,tc,head=0,tail=1;
27         for(i=1;i<=n;i++) for(j=1;j<=n;j++) for(k=0;k<=m;k++) dis[i][j][k]=inf;
28         q[0]=que(1,1,m);vis[1][1][m]=1;dis[1][1][m]=0;
29         while(head<tail){
30             x=q[head].x;y=q[head].y;z=q[head++].z;vis[x][y][z]=0;
31     //        cout<<"spfa "<<x<<ends<<y<<ends<<z<<ends<<dis[x][y][z]<<endl;
32             for(i=1;i<=4;i++){
33                 tx=x+dx[i];ty=y+dy[i];
34                 if(tx<1||tx>n||ty<1||ty>n) continue;
35                 tz=(a[tx][ty]?m:(z-1));tc=dis[x][y][z];
36                 if(a[tx][ty]) tc+=k1;
37                 if(i<=2) tc+=k2;
38                 if(z==0) tz=(a[tx][ty]?m:(m-1)),tc+=k3+k1;
39     //            cout<<"    to "<<tx<<ends<<ty<<ends<<tz<<ends<<tc<<ends<<dis[tx][ty][tz]<<endl;
40                 if(tc<dis[tx][ty][tz]){
41                     dis[tx][ty][tz]=tc;
42                     if(!vis[tx][ty][tz]){
43                         q[tail++]=que(tx,ty,tz);vis[tx][ty][tz]=1;
44                     }
45                 }
46             }
47         }
48     }
49     int main(){
50         freopen("trav.in","r",stdin);
51         freopen("trav.out","w",stdout);
52         int i,j,k,ans=inf;
53         n=read();m=read();k1=read();k2=read();k3=read();
54         for(i=1;i<=n;i++) for(j=1;j<=n;j++) a[i][j]=read();
55         spfa();
56     //    for(i=1;i<=n;i++){
57     //        for(j=1;j<=n;j++){
58     //            for(k=0;k<=m;k++) cout<<dis[i][j][k]<<ends;
59     //        }
60     //        cout<<endl;
61     //    }
62         for(i=0;i<=m;i++) ans=min(ans,dis[n][n][i]);
63         printf("%d",ans);
64     }