【HDOJ】1242 Rescue

BFS+优先级队列。

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

 #define MAXNUM 205

 typedef struct node_st {
     int x, y ,t;
     node_st() {}
     node_st(int xx, int yy, int tt) {
         x = xx; y = yy; t = tt;
     }
     friend bool operator < (node_st a, node_st b) {
         return a.t > b.t;
     }
 } node_st;

 int n, m;
 char map[MAXNUM][MAXNUM];
 char visit[MAXNUM][MAXNUM];
 int direct[][] = {{,},{-,},{,-},{,}};

 int bfs(int x, int y) {
     priority_queue<node_st> que;
     node_st node;
     int i, t;

     que.push(node_st(x, y, ));
     memset(visit, , sizeof(visit));
     visit[x][y] = ;

     while ( !que.empty() ) {
         node = que.top();
         if (map[node.x][node.y] == 'a')
             return node.t;
         que.pop();
         t = node.t + ;
         for (i=; i<; ++i) {
             x = node.x + direct[i][];
             y = node.y + direct[i][];
             if (x< || x>=n || y< || y>=m)
                 continue;
             if (visit[x][y] || map[x][y]=='#')
                 continue;
             if (map[x][y] == 'x')
                 que.push(node_st(x,y,t+));
             else
                 que.push(node_st(x,y,t));
             visit[x][y] = ;
         }
     }

     return -;
 }

 int main() {
     int i, j, t;
     int begx, begy;

     while (scanf("%d %d", &n, &m) != EOF) {
         for (i=; i<n; ++i) {
             scanf("%s", map[i]);
             for (j=; j<m; ++j) {
                 if (map[i][j] == 'r') {
                     begx = i;
                     begy = j;
                 }
             }
         }
         t = bfs(begx, begy);
         if (t == -)
             printf("Poor ANGEL has to stay in the * all his life.\n");
         else
             printf("%d\n", t);
     }
     return ;
 }