学步园

算法很简单，直接贴代码啦

#include <iostream>

using namespace std;

template<typename T>
int binary_search(const T s[],const int size,const T &m)
{
 if(size <= 0){
  return -1;
 }
 int i = size/2;
 int k = 1;
 int step = 1;

 while(step > 0 && i >= 0 && i < size){
  step = size/(2*++k);
  if(m == s[i]){
   return i;
  }else if(m > s[i]){
   i += step;
  }else{
   i -= step;
  }
 }

 return -1;
}

int main()
{
 long s[]={1,3,5,6,19,27,38,45,687,6789,10000};
 
 int len = sizeof(s)/sizeof(long);

 cout<<"0:"<<binary_search<long>(s,len,1)<<endl;
 cout<<"1:"<<binary_search<long>(s,len,3)<<endl;
 cout<<"5:"<<binary_search<long>(s,len,27)<<endl;
 cout<<"10:"<<binary_search<long>(s,len,10000)<<endl;
 cout<<"-1:"<<binary_search<long>(s,len,10001)<<endl;
 cout<<"-1:"<<binary_search<long>(s,len,44)<<endl;
 cout<<"-1:"<<binary_search<long>(s,len,0)<<endl;

 return 0;
}