HDU 1242

简单题

 #include <iostream>
 #include <cstdio>
 #include <queue>
 using namespace std;

 const int MAX=;
 const int inf=;
 int tim[MAX][MAX];
 char maze[MAX][MAX];
 int n,m;
 int ai,aj;
 typedef struct c{
     int i,j,ti;
     bool operator <(const c &A)const {
         if(ti>A.ti) return true;
         return false;
     }
 }Node;
 Node tmp,pushed;
 priority_queue<Node>que;
 int dir[][]={,,,-,,,-,};

 bool ok(int i,int j){
     if(i>=&&i<n&&j>=&&j<m&&maze[i][j]!='#')
     return true;
     return false;
 }

 bool bfs(){
     int ti,tj;
     while(!que.empty()){
         tmp=que.top();
         que.pop();
         if(maze[tmp.i][tmp.j]=='r'){
             printf("%d\n",tmp.ti);
             return true;
         }
         for(int i=;i<;i++){
             ti=tmp.i+dir[i][];
             tj=tmp.j+dir[i][];
             if(ok(ti,tj)){
                 if(maze[ti][tj]=='.'||maze[ti][tj]=='r'){
                     if(tmp.ti+<tim[ti][tj]){
                         tim[ti][tj]=tmp.ti+;
                         pushed.i=ti; pushed.j=tj; pushed.ti=tmp.ti+;
                         que.push(pushed);
                     }
                 }
                 else if(maze[ti][tj]=='x'){
                     if(tmp.ti+<tim[ti][tj]){
                         tim[ti][tj]=tmp.ti+;
                         pushed.i=ti; pushed.j=tj; pushed.ti=tmp.ti+;
                         que.push(pushed);
                     }
                 }
             }
         }
     }
     return false;
 }

 int main(){
     while(scanf("%d%d",&n,&m)!=EOF){
         for(int i=;i<n;i++){
             scanf("%s",maze[i]);
             for(int j=;j<m;j++){
                 if(maze[i][j]=='a'){
                     ai=i; aj=j;
                 }
                 tim[i][j]=inf;
             }
         }
         tim[ai][aj]=;
         tmp.i=ai; tmp.j=aj; tmp.ti=;
         que.push(tmp);
         if(!bfs()){
             printf("Poor ANGEL has to stay in the prison all his life.\n");
         }
         while(!que.empty())
         que.pop();
     }
     return ;
 }