FZU 2285 迷宫寻宝

思路：

bfs求最短路径。

 #include<stdio.h>
 #include<iostream>
 #include<queue>
 #include<cstring>
 #define maxn 105
 using namespace std;
 int sx, sy, ex, ey;
 char map[][];
 char vis[][];
 int dic[][] = { { -, },{ ,- },{ , },{ , } };//4个方向
 int res;
 struct node {
     int x, y, step;
 };
 int n;
 bool check(int x, int y)
 {
     if (x >=  && x < n&&y >=  && y < n&&map[x][y] != '#'&&vis[x][y] !=)
         return true;
     //printf("x=%d y=%d c=%c\n", x, y,map[x][y]);
     return false;
 }

 void bfs()
 {
     queue<node> q;
     node a;
     node next;
     a.x = sx;
     a.y = sy;
     a.step = ;
     vis[a.x][a.y] = ;
     q.push(a);
     while (!q.empty())
     {
         a = q.front();
         q.pop();
         for (int i = ; i<; i++)
         {
             next = a;
             next.x += dic[i][];
             next.y += dic[i][];
             next.step = a.step + ;
             if (next.x == ex&&next.y == ey)//找到出口
             {
                 res = next.step;
             //    printf("res=%d\n", res);
                 return;
             }
             if (check(next.x, next.y))//检查合法性
             {
                 vis[next.x][next.y] = ;
                 //printf("vis[%d][%d]=1\n", next.x, next.y);
                 q.push(next);
             }
         }
     }
     res = -;
 }
 int main()
 {
     while (scanf("%d", &n) == )
     {
         for (int i = ; i<n; i++)
             scanf("%s", &map[i]);
         memset(vis, , sizeof(vis));
         //for (int i = 0; i < n; i++)
             //printf("%s\n", map[i]);
         for (int i = ; i<n; i++)
         {
             for (int j = ; j<n; j++)
             {
                 if (map[i][j] == 'S')
                 {
                     sx = i;
                     sy = j;
                 }
                 if (map[i][j] == 'E')
                 {
                     ex = i;
                     ey = j;
                 }
             }
         }
         //printf("sx=%d sy=%d ex=%d ey=%d\n", sx, sy, ex, ey);
         bfs();
         printf("%d\n", res);
     }
     return ;
 }