猫吃老鼠的STL实现

#include < vector >
#include < iostream >

using namespace std;

int eat(const int total, const int space)
{
   if (total <= 0 || space <= 0)
   {
      return -1;
   }

   vector           v;
   vector::iterator it;

   // 初使化向量
   for (int i = 1; i <= total; ++i)
   {
      v.push_back(i);
   }

   int j = 1;
   it   = v.begin();
   while (v.size() > 1)
   {
      // 如果数到第m个，则删除它，并且从头开始数
      // 迭代器不需要后移，因为删除之后自动就指向下一个元素
      if (space == j)
      {
         v.erase(it);
         j = 1;
      }
      else
      {
         ++it;
         ++j;
      }

      // 如果到最后了，让迭代器指向第一个元素
      if (it >= v.end())
      {
         it = v.begin();
      }
   }

   // 现在只有一个元素了，那么第一个元素就是我们需要的
   return (*v.begin());
}

void main( void )
{
   int total;
   int space;

   total = 5;
   space = 1;
   cout << "总共: " << total << "  "
       << "间隔: " << space << "  "
       << "最后: " << eat(total, space) << endl;

   total = 5;
   space = 2;
   cout << "总共: " << total << "  "
       << "间隔: " << space << "  "
       << "最后: " << eat(total, space) << endl;

   total = 5;
   space = 3;
   cout << "总共: " << total << "  "
       << "间隔: " << space << "  "
       << "最后: " << eat(total, space) << endl;
   
}