暑假集训(1)第八弹 -----Catch the cow（Poj3984)

#include "cstdio"
#include "iostream"
#include "queue"

using namespace std;
int a[5][5];
struct person
{
   int i;
   int j;
};
void abegin()
{
    for (int i=0;i<5;i++)
      for (int j=0;j<5;j++)
        cin>>a[i][j];
}
void print()
{
  int i=0,j=0;
   printf ("(%d, %d)\n",i,j);
   while (i != 4 || j != 4)
   {
     switch(a[i][j])
     {
       case 3: i--; break;
       case 4: i++; break;
       case 5: j--; break;
       case 6: j++; break;
       default: continue;
     }
     printf ("(%d, %d)\n",i,j);
   }
}
void bfs ()
{
  queue<person> p;
  person fir,sec;
  fir.i = 4;
  fir.j = 4;
  a[fir.i][fir.j] = 2;
  p.push(fir);
  while (!p.empty())
  {
     sec = p.front();
     p.pop();
     if (sec.i>0 && a[sec.i-1][sec.j] < 1)
                   {
                       fir.i=sec.i-1;
                       fir.j=sec.j;
                       a[fir.i][fir.j] = 4;
                       p.push(fir);
                   }
     if (sec.i<4 && a[sec.i+1][sec.j] < 1)
                  {
                      fir.i=sec.i+1;
                      fir.j=sec.j;
                      a[fir.i][fir.j] = 3;
                      p.push(fir);
                  }
     if (sec.j>0 && a[sec.i][sec.j-1] < 1)
                  {
                      fir.i=sec.i;
                      fir.j=sec.j-1;
                      a[fir.i][fir.j] = 6;
                      p.push(fir);
                  }
     if (sec.j<4 && a[sec.i][sec.j+1] < 1)
                   {
                       fir.i=sec.i;
                       fir.j=sec.j+1;
                       a[fir.i][fir.j] = 5;
                       p.push(fir);
                   }

        if (a[0][0] != 0)
        {
            print ();
            return;
        }
  }
}
int main()
{
         abegin();
          bfs();
    return 0;
}