最接近點對問題

 

#include <iostream>
using namespace std;

#define INF 1e10
#define MAX_NUM 100


template<class T>
inline T min(T a,T b,T c)
{
 T tmp;
 return (tmp = a<b?a:b)<c?tmp:c;
}


bool Cpairl(int a[], int &d, int n)
{
 if( n<2 )
 {
  d = INF;
  return false;
 }

 if(n > MAX_NUM)
 {
  cerr<<"MAX_NUM Error"<<endl;
 }

 int total_num = 0;
 for(int i = 0;i < n; i++)
  total_num += a[i];
 double average_num = total_num/n;
 int a1[MAX_NUM],a2[MAX_NUM];
 int i = 0;
 while(a[i]<average_num)
  a1[i++] = a[i];
 int d1 = INF, d2 = INF, size_d = i;
 Cpairl(a1,d1,size_d);
 while(i<n)
  a2[(i++)-size_d] = a[i];
 Cpairl(a2,d2,i-size_d);
 int p = a1[size_d-1];
 int q = a2[0];
 d = min(d1,d2,q-p);

 return true;
}