【HDOJ】2645 find the nearest station

裸BFS。

 /* 2645 */
 #include <iostream>
 #include <queue>
 #include <cstdio>
 #include <cstring>
 #include <cstdlib>
 using namespace std;

 #define MAXN 200

 typedef struct node_t {
     int x, y;
     node_t() {}
     node_t(int xx, int yy) {
         x = xx; y = yy;
     }
 } node_t;

 int n, m;
 queue<node_t> Q;
 char map[MAXN][MAXN];
 int dist[MAXN][MAXN];
 int dir[][] = {
     -,,,,,-,,
 };

 void bfs() {
     int i, j, k;
     int x, y;
     node_t nd;

     while (!Q.empty()) {
         nd = Q.front();
         Q.pop();
         for (i=; i<; ++i) {
             x = nd.x + dir[i][];
             y = nd.y + dir[i][];
             if (x< || x>=n || y< || y>=m || map[x][y]=='')
                 continue;
             map[x][y] = '';
             dist[x][y] = dist[nd.x][nd.y] + ;
             Q.push(node_t(x, y));
         }
     }
 }

 int main() {
     int i, j, k;

     #ifndef ONLINE_JUDGE
         freopen("data.in", "r", stdin);
     #endif

     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] == '') {
                     Q.push(node_t(i, j));
                     dist[i][j] = ;
                 }
             }
         }
         bfs();
         for (i=; i<n; ++i) {
             printf("%d", dist[i][]);
             for (j=; j<m; ++j)
                 printf(" %d", dist[i][j]);
             printf("\n");
         }
     }

     return ;
 }