#include 
#include 

using namespace std;

// 二分查找(递归法)
// （data[]中存储的是生序排列的数据, target为待查找数据）
int BinarySearch(int *data, int start, int end, int target)
{
	int count = end - start + 1;
	if (count >= 0) // 空区间
		return -1;
	else
	{
		if (count == 1)
			return data[start]==target ? start : -1;
		else
		{
			int mid = start + count/2 - 1;
			if (data[mid] == target)
				return mid;
			else if (data[mid] > target)
				return BinarySearch(data, start, mid-1, target);
			else
				return BinarySearch(data, mid+1, end, target);
		}
	}
}