【问题描述】输入一批从小到大的整数，以回车结束，存入列表中。再输入一个要查找的数，输出此数在列表中的索引位置，如不存在则输出﹣1。用扫描法或者二分法都可以 【输入形式】 【输出形式】 【样例输入输出】 Enter a number (< Enter > to quit ):1 Enter a number (< Enter > to quit ):2 Enter a number (< Enter > to quit ):5 Enter a number (< Enter > to quit ):6 Enter a number (< Enter > to quit ):8 Enter a number (< Enter > to quit ):10 Enter a number (< Enter > to quit ): Enter a number searched :8 【样例说明】8在列表索引值为4的位置上【评分标准】Python语言

以下是Python代码实现，采用二分查找法：

def binary_search(num_list, target):
    left = 0
    right = len(num_list) - 1
    while left <= right:
        mid = (left + right) // 2
        if num_list[mid] == target:
            return mid
        elif num_list[mid] > target:
            right = mid - 1
        else:
            left = mid + 1
    return -1

num_list = []
while True:
    num_str = input("Enter a number (<Enter> to quit):")
    if num_str == "":
        break
    num_list.append(int(num_str))

target = int(input("Enter a number searched:"))

result = binary_search(num_list, target)

if result == -1:
    print("Target not found")
else:
    print("Target found at index", result)

输入样例：

Enter a number (<Enter> to quit):1
Enter a number (<Enter> to quit):2
Enter a number (<Enter> to quit):5
Enter a number (<Enter> to quit):6
Enter a number (<Enter> to quit):8
Enter a number (<Enter> to quit):10
Enter a number (<Enter> to quit):

Enter a number searched:8

输出样例：

Target found at index 4