pythone二分查找

以下是两种Python实现二分查找算法的方法：

方法一：

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

arr = [1, 3, 6, 9, 10, 20, 30]
x = 10

result = binary_search(arr, 0, len(arr) - 1, x)

if result != -1:
    print("元素在数组中的索引为", str(result))
else:
    print("元素不在数组中")

方法二：

def binary_search(arr, x):
    low = 0
    high = len(arr) - 1
    mid = 0

    while low <= high:
        mid = (high + low) // 2

        if arr[mid] < x:
            low = mid + 1

        elif arr[mid] > x:
            high = mid - 1

        else:
            return mid

    return -1

arr = [1, 3, 6, 9, 10, 20, 30]
x = 10

result = binary_search(arr, x)

if result != -1:
    print("元素在数组中的索引为", str(result))
else:
    print("元素不在数组中")