boj1301

http://acm.scs.bupt.cn/onlinejudge/showproblem.php?problem_id=1301

就是普通的广度优先搜索，不过需要在搜索的过程中记录状态，数据结构写起来稍微麻烦一点儿。WA好多次，一直没找到原因，非常郁闷。由于马上要用到了，就又检查了几遍，还是没找到哪儿错了。最后实在没办法了把队列由1000改为2000就过了！！！郁闷！！！已经有好几次倒在数组开得太小上了！！！以后一定要开大点儿。

下面是源代码，写的不好，有时间会改进一下的。

 

#include<iostream>
#include<string>
using namespace std;

struct Queue
{
    int x,y,father;
    int step,index;
    char method;
};
Queue queue[1000],game_end;
char board[20][20],output_array[1000];
int n,queue_start,queue_end,start_x,start_y,end_x,end_y,r,c,game_is_end,sum;
int dx[4] = {1,-1,0,0},dy[4] = {0,0,1,-1};
void walk();
void output();
int main()
{
    sum = 0;
    int i,j,k;
    char temp;
    while(cin>>r>>c)
    {
       game_is_end = 0;
       queue_start = 0;
       queue_end = 0;
       for (i = 0;i < r;i++)
       {
       for (j = 0;j < c;j++)
       {
           cin>>temp;
           board[i][j] = temp;
           if(temp == 'S')
           {
                   start_x = i;
                   start_y = j;
           }
           else
           if (temp == 'E')
           {
                    end_x = i;
                    end_y = j;
           }
       }
       }
       walk();
    }
   
    return 0;
}

void walk()
{
     int i,j,k,temp_i,temp_j;
     Queue temp_node;
     queue[queue_end].x = start_x;
     queue[queue_end].y = start_y;
     queue[queue_end].father = -1;
     queue[queue_end].step = 0;
     queue[queue_end].index = 0;
     queue_end++;
     while(queue_start < queue_end && !game_is_end )
     {
         temp_node = queue[queue_start];
         queue_start++;
         for (i = 0;i < 4;i++)
         {
             temp_i = temp_node.x;
             temp_j = temp_node.y;
             while(board[temp_i][temp_j] != '#' && temp_i >=0 && temp_i < r && temp_j >= 0 && temp_j < c && !game_is_end)
             {
                if (temp_i == end_x && temp_j == end_y)
                {
                           game_is_end = 1;
                           game_end.x = temp_i;
                           game_end.y = temp_j;
                           game_end.father = temp_node.index;
                           game_end.step = temp_node.step + 1;
                           game_end.index = queue_end;
                           queue_end++;
                           switch(i)
                           {
                                    case 0: game_end.method = 'd';break;
                                    case 1: game_end.method = 'u';break;
                                    case 2: game_end.method = 'r';break;
                                    case 3: game_end.method = 'l';break;
                           }
                           output();
                           break;
                          
                }
                temp_i = temp_i + dx[i];
                temp_j = temp_j + dy[i];
               
             }
             if (board[temp_i][temp_j] == '#' && temp_i >=0 && temp_i < r && temp_j >= 0 && temp_j < c && !game_is_end)
             {
                 
                     if (!((temp_i == temp_node.x + dx[i]) && (temp_j == temp_node.y + dy[i])))
                     {
                        temp_i -= dx[i];
                        temp_j -= dy[i];         
                        queue[queue_end].father = temp_node.index;
                        queue[queue_end].step = temp_node.step +1;
                        queue[queue_end].index = queue_end;
                        queue[queue_end].x = temp_i;
                        queue[queue_end].y = temp_j;
                        switch(i)
                        {
                              case 0: queue[queue_end].method = 'd';break;
                              case 1: queue[queue_end].method = 'u';break;
                              case 2: queue[queue_end].method = 'r';break;
                              case 3: queue[queue_end].method = 'l';break;
                        }
                        queue_end++;
                     }
                                 
             }
         }
                      
     }
}

void output()
{
     Queue temp_queue_node;
     int i,j,k;
     i = game_end.father;
     temp_queue_node = game_end;
     cout<<"Case "<<++sum<<":"<<endl;
     cout<<game_end.step<<endl;
     j = game_end.step;
     while(j)
     {
         output_array[j-1] = temp_queue_node.method;
         i = temp_queue_node.father;
         temp_queue_node = queue[i];
         j--;  
     }
     j = game_end.step;
     for(k = 0;k < j;k++)
     {
           cout<<output_array[k];
     }
     cout<<endl;
   
}