关于Ackermann函数的计算方法

//带备忘的二维辅助空间计算Ackermann
int Ackermann(m,   n)   {
  1.   if   A[m,n]   >=   0     
  2.         then   return   A[m,   n];   
  3.   else   if   m   =   0   and   n   >   0   
  4.         then   A[m,n]   <-   n   +   1;   
  5.   else   if   n   =   0   and   m   >   0   
  6.         then   A[m,n]   <-   Ackermann(m-1,   1);   
  7.   else   if   n   >   0   and   m   >   0   
  8.         then   A[m,n]   <-   Ackermann(m-1,   Ackermann(m,   n-1));   
  9.   return   A[m,   n];
}
//带备忘的二维辅助空间计算Ackermann
int Ackermann(m,   n)