使用递归二进制搜索查找未知对象

def binary_search_recursive(arr, target, low, high):
    if high >= low:
        mid = (high + low) // 2
        if arr[mid] == target:
            return mid
        elif arr[mid] > target:
            return binary_search_recursive(arr, target, low, mid - 1)
        else:
            return binary_search_recursive(arr, target, mid + 1, high)
    else:
        return -1

# 示例用法
arr = [2, 3, 4, 10, 40]
target = 10
result = binary_search_recursive(arr, target, 0, len(arr) - 1)
if result != -1:
    print("元素在数组中的索引为", result)
else:
    print("元素不在数组中")

def binary_search_iterative(arr, target):
    low = 0
    high = len(arr) - 1
    while low <= high:
        mid = (high + low) // 2
        if arr[mid] == target:
            return mid
        elif arr[mid] > target:
            high = mid - 1
        else:
            low = mid + 1
    return -1

# 示例用法
arr = [2, 3, 4, 10, 40]
target = 10
result = binary_search_iterative(arr, target)
if result != -1:
    print("元素在数组中的索引为", result)
else:
    print("元素不在数组中")