1360. 日期之间隔几天

请你编写一个程序来计算两个日期之间隔了多少天。

日期以字符串形式给出，格式为 YYYY-MM-DD，如示例所示。

示例 1：

输入：date1 = "2019-06-29", date2 = "2019-06-30"
输出：1
示例 2：

输入：date1 = "2020-01-15", date2 = "2019-12-31"
输出：15
 

提示：

给定的日期是 1971 年到 2100 年之间的有效日期。

来源：力扣（LeetCode）
链接：https://leetcode-cn.com/problems/number-of-days-between-two-dates

class Solution:
    def daysBetweenDates(self, date1: str, date2: str) -> int:
        return abs(datetime.datetime.strptime(date1,'%Y-%m-%d')-datetime.datetime.strptime(date2,'%Y-%m-%d')).days

class Solution:
    def daysBetweenDates(self, date1: str, date2: str) -> int:
        import datetime
        date1 = map(int, date1.split("-"))
        date2 = map(int, date2.split("-"))
        date1 = datetime.date(*date1)
        date2 = datetime.date(*date2)
        return abs((date1-date2).days)

class Solution:
    def daysBetweenDates(self, date1: str, date2: str) -> int:
        month_run = [31,29,31,30,31,30,31,31,30,31,30,31]
        month_normal = [31,28,31,30,31,30,31,31,30,31,30,31]

        if date1 > date2:
            date1, date2 = date2, date1

        def simplify_number(number_string):

            if number_string[0] == 0:
                number = int(number_string[1:])
            else:
                number = int(number_string)
            return number

        def if_run_nian(year):
            return year % 100 != 0 and year % 4 == 0 or year % 400 ==0 

        year1 = simplify_number(date1[0:4])
        year2 = simplify_number(date2[0:4])
        day1 = simplify_number(date1[8:])
        day2 = simplify_number(date2[8:])
        month1 = simplify_number(date1[5:7])
        month2 = simplify_number(date2[5:7])
        delta_year = year2 - year1
        delta_month = abs(month2 - month1)
        day = 0

        if delta_year >= 2:
            for i in range(1,delta_year):
                if if_run_nian(year1+i):
                    day += 366
                else:
                    day += 365

        if if_run_nian(year1):
            month_list1 = month_run
        else:
            month_list1 = month_normal
        if if_run_nian(year2):
            month_list2 = month_run
        else:
            month_list2 = month_normal

        if delta_year >= 1:
            for i in range(month1, 12):
                day += month_list1[i]
            for k in range(0,month2-1):
                day += month_list2[k]
            day = day + (month_list1[month1-1] - day1) + day2
        else:
            if delta_month == 0:
                day = day + day2 - day1
            elif delta_month == 1:
                day = day + (month_list1[month1-1] - day1) + day2
            else:
                day = day + (month_list1[month1-1] - day1) + day2
                for i in range(month1,month2-1):
                    day += month_list1[i]
        
        return day

class Solution:
    def daysBetweenDates(self, date1: str, date2: str) -> int:
        months = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
        def if_run_nian(year):
            return year % 100 != 0 and year % 4 == 0 or year % 400 ==0 
        def cnt_day(date):
            y, m, total = map(int, date.split("-"))
            for i in range(1971, y):
                total += 366 if if_run_nian(i) else 365
            for i in range(m):
                total += months[i]
            if m > 2 and if_run_nian(y):
                total += 1
            return total 
        return abs(cnt_day(date2) - cnt_day(date1))