leetcode1154. 一年中的第几天

python

def dayOfYear(self, date: str) -> int:
    year, month, day = [int(i) for i in date.split("-")]
    arr = [31,28,31,30,31,30,31,31,30,31,30,31]
    if year % 400 == 0 or year % 4 == 0 and year % 100 != 0:
        arr[1] += 1
    return day + sum(arr[:month-1])

一周中的第几天 只需在这道题的基础上稍作修改即可

leetcode1185. 一周中的第几天

因为题目给出的年份是从1971到2100，而我们通过查阅知道1970.12.31是星期四

所以通过判断距1970.12.31的天数就能知道题目给出的那天是星期几

在 一年中的第几天 的基础上加上之前年份的天数就可以了

python

def dayOfTheWeek(self, day: int, month: int, year: int) -> str:
    week = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday","Sunday"]
    days = 0
    # 加上年份贡献的天数
    days += 365*(year-1971) + (year-1969)//4
    arr = [31,28,31,30,31,30,31,31,30,31,30,31]
    if year % 400 == 0 or year % 4 == 0 and year % 100 != 0:
        arr[1] += 1
    days += day + sum(arr[:month-1]) 
    return week[(days+3)%7]        

或者直接用python库中的函数帮我们求解

        week = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday","Sunday"]
        
        return week[date.weekday(date(year,month,day))]