'''
Author: SJ2050
Date: 2021-10-16 22:14:07
LastEditTime: 2021-10-16 22:19:04
Version: v0.0.1
Description: Solution for homework5.
Copyright © 2021 SJ2050
'''

if __name__ == '__main__':
    i = 2
    res = 0
    while i <= 100:
        res += (-1)**(i&1)*i
        i += 1

    print(f'result: {res}')

    # 可以使用列表推导式一句话写完
    res = sum([(-1)**(i&1)*i for i in range(2, 101)])

    print(f'result: {res}')