题解 | 2024/10/12（模拟）（Python）

注意点

（1）只需枚举年份以缩短时间复杂度

（2）闰年判定及二月天数的修改

def f(year: int) -> None:  # 修改 2 月的天数
    months[2] = 29
    if year % 400 == 0:
        return
    if year % 4 == 0 and year % 100 != 0:
        return
    months[2] = 28
    return

months = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]

start_date = input()
end_date = input()

start_year = int(start_date[ : 4])
end_year = int(end_date[ : 4])

ans = 0
for year in map(str, range(start_year, end_year + 1)):
    date = year + year[ : : -1]
    # 只需判定 date 是否为合法的日期
    if date < start_date or date > end_date:  # 在规定范围内
        continue
    month = int(date[4 : 6])
    day = int(date[6 : 8])
    f(int(year))  # 修改天数
    if 1 <= month <= 12 and 1 <= day <= months[month]:
        ans += 1
print(ans)