POJ 3037 Skiing

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<queue>
 4 #include<cstring>
 5 #include<cmath>
 6 using namespace std;
 7 const int maxn=105;
 8 const double Max_double=11258999068426240000;
 9 bool exist[maxn][maxn];
10 struct node{
11     int x,y;
12 };
13 node p;
14 double dis[maxn][maxn];
15 int map[maxn][maxn],v,n,m;
16 int dir[][2]={{0,-1},{1,0},{0,1},{-1,0}};
17 queue<node>q;
18 double SPFA(){
19     p.y=1;p.x=1;
20     dis[1][1]=0;exist[1][1]=true;
21     q.push(p);
22     while(!q.empty()){
23         p=q.front();q.pop();
24         exist[p.x][p.y]=false;
25         double k=1.0/(v * pow(2, 1.0*(map[1][1]-map[p.x][p.y])));
26         for(int i=0;i<4;i++){
27             int nex=p.x+dir[i][0],ney=p.y+dir[i][1];
28             if(nex>=1&&nex<=n&&ney>=1&&ney<=m){
29                 if(dis[nex][ney]>dis[p.x][p.y]+k){
30                     dis[nex][ney]=dis[p.x][p.y]+k;
31                     if(exist[nex][ney]==false){
32                         node tmp;
33                         tmp.x=nex;tmp.y=ney;
34                         q.push(tmp);exist[nex][ney]=true;
35                     }
36                 }
37             }
38         }
39     }
40     return dis[n][m];
41 }
42 int main()
43 {
44     scanf("%d%d%d",&v,&n,&m);
45     for(int i=1;i<=n;i++)
46       for(int j=1;j<=m;j++){
47           scanf("%d",&map[i][j]);dis[i][j]=Max_double;
48       }
49     memset(exist,false,sizeof(exist));
50     printf("%.2lf\n",SPFA());
51     return 0;
52 }