【算法】分治算法

#include<iostream>
using namespace std;

//递归实现二分查找
//找到这个值最后一级一级的传递return回来
int BinarySearch(int* arr,int minSub,int maxSub,int num)
{
	if (minSub > maxSub)//无解
	{
		return -1;
	}
	int mid = (minSub + maxSub) / 2;
	if (num == arr[mid])
	{
		return mid;
	}
	else if(num < arr[mid])
	{
		//因为中间数据arr[mid]大于num,所以新的范围从minSub到mid-1
		return BinarySearch(arr, minSub, mid - 1, num);
	}
	else//num > arr[mid]
	{
		//因为num大于中间数据arr[mid],所以新的范围从mid+1到maxSub
		return BinarySearch(arr, mid + 1, maxSub, num);
	}
}

int main(void)
{
	int arr[] = { 5,7,9,11,17,23,48,55,64 };
	//数组-起始位置(数组索引范围)-要查找的值
	int index = BinarySearch(arr,0,8,64);
	cout << index << endl;
	return 0;
}