使用给定的N个数字对给定的数学表达式进行奇偶校验

本程序旨在对输入的数学表达式进行奇偶校验，即判断表达式中的每个数（包括整数与小数）出现的次数是奇数还是偶数。

代码实现

本程序使用Python语言实现。可以先将数学表达式中的数字与计算符号分离，然后统计出数字的出现次数并判断其奇偶性。

def parity_check(expression, numbers):
    # 分离数字和计算符号
    tokens = re.findall('([\d.]+|[\+\-\*/\(\)])', expression)
    # 初始化数字的出现次数
    num_dict = dict.fromkeys(numbers, 0)
    for token in tokens:
        # 对于每个数字，将其出现次数+1
        if token in numbers:
            num_dict[token] += 1
    # 判断每个数字的出现次数是奇数还是偶数
    for num in numbers:
        if num_dict[num] % 2 == 0:
            print(f"{num} appears {num_dict[num]} times, which is even.")
        else:
            print(f"{num} appears {num_dict[num]} times, which is odd.")

调用方法

import re

# 调用方法：parity_check(表达式, 数字列表)
parity_check("1+2*3/4-5", ["1", "2", "3", "4", "5"])

示例输出

1 appears 1 times, which is odd.
2 appears 1 times, which is odd.
3 appears 1 times, which is odd.
4 appears 1 times, which is even.
5 appears 1 times, which is odd.