二分查找递归实现

• 1.python
• 2.java
• 3.C++

def binary_Search(Array, num,small_num=None,high_num=None):
    small_num = small_num if small_num else 0
    high_num = high_num if high_num is not None else len(Array) - 1
    mid_num = (high_num + small_num) // 2
    if small_num <= high_num:
            if num > Array[mid_num]:
            	return binary_Search(Array,num,mid_num+1,high_num)
            elif num < Array[mid_num]:
            	return  binary_Search(Array, num, small_num,mid_num-1)
            else :
            	return mid_num
    else:
            return '%s值不存在'%num
lis = [99, 222, 444, 544, 555, 567, 777, 786, 787, 991, 998, 5555, 8877]
ret = binary_Search(lis,555)
print('索引值为%s,对应值为%s'%(ret,lis[ret]))

package Package01;



public class BinarySearch {
    public static void main(String[] args) {
        int arr[] = {1,8,10,89,1000,1234};

        int resIndex = binarySearch(arr,0,arr.length-1,1);

        System.out.println("resIdex=" + resIndex);

        }


    //二分查找算法
    

    public static int binarySearch(int[] arr, int left, int right, int findVal){
        if (left > right) {
            return -1;
        }

        int mid = (left+right)/2;
        int midVal = arr[mid];

        if(findVal > midVal){
            //向右递归
            return binarySearch(arr,mid+1,right,findVal);

        }else if(findVal < midVal){
            return binarySearch(arr,left,mid-1,findVal);
        }else{
            return mid;
        }

    }
    
    }

#include
using namespace std;
int binarySearch(int *arr , int low , int high , int target)//递归实现
{
	int middle = (low + high)/2;
	if(low > high)
		return -1;
	if(arr[middle] == target)
		return middle;
	if(arr[middle] > target)
		return binarySearch( arr , low , middle - 1 , target);
	if(arr[middle] < target)
		return binarySearch( arr , middle + 1 , high , target);
 
};

int main()
{
	int a[10] = {5,6,7,8,9, 10 , 11, 12 ,13, 14};
	int index = binarySearch( a , 0 , 9 , 12);
	cout<