模板：二分搜索技术

代码如下：

 1 template <class T> int binarySearch(const T* pt, int n, T t)

 2 

 3 {

 4  int head = 0, tail = n-1;

 5  int i;

 6  while (tail >= head)

 7  {

 8   i = (head + tail) / 2;

 9   if (t == pt[i])

10    return i;

11   if (t < pt[i])

12    tail = i - 1;

13   else

14    head = i + 1;

15  }

16  return -1;

17 }

参考：

http://chenkegarfield.blog.163.com/blog/static/62330008200911191540807/