一些笔试题目

求一个表格的最左上顶点到最右下顶点的路线数目

答案：组和数（n+m）!/(n!*m!)

nm = n+m;
product = 1;
   while(n>0)
   {
      product *= nm/n;
      nm--;
      n--;
    }
  while(m>0)
   {
      product *= nm/m;
      nm--;
      n--;
   }
while(nm>0)
{
   product *= nm;
  nm--;
}

void f(double nm, double n, double m)
{
if(n==0 || n==1) n = 1;
if(m==0 || m==1) m = 1;
if (nm == 1 || nm ==0) return 1;
else return (nm/n/m)*f(nm/n);
}