View Compilation Error

0_0_19416655_6623.cpp: In function 'void set_fac()':
0_0_19416655_6623.cpp:14:5: error: 'fac' was not declared in this scope
     fac[0]=1;
     ^
0_0_19416655_6623.cpp: In function 'int cantor(int*)':
0_0_19416655_6623.cpp:25:16: error: 'fac' was not declared in this scope
         ans+=k*fac[8-i];
                ^
0_0_19416655_6623.cpp: In function 'void bfs(int*)':
0_0_19416655_6623.cpp:38:5: error: 'Node' was not declared in this scope
     Node[q.ctor].pre=0;//把最终目标父节点记为0，也就是本身  
     ^
0_0_19416655_6623.cpp:46:22: error: 'sx' was not declared in this scope
             tx=q.n%3+sx[i];//一维转二维
                      ^
0_0_19416655_6623.cpp:47:13: error: 'sy' was not declared in this scope
    ty=q.n/3+sy[i];
             ^