1360.cpp

int mon[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
class Solution {
public:
    int get(string date)
    {
        int year=0,month=0,day=0;
        for(int i=0;i<4;i++)
        {
            year=year*10+date[i]-'0';
        }
        for(int i=5;i<7;i++)
        {
            month=month*10+date[i]-'0';
        }
        for(int i=8;i<10;i++)
        {
            day=day*10+date[i]-'0';
        }
        int res=0;
        for(int i=1971;i<year;i++)
        {
            res=res+365;
            if((i%4==0&&i%100!=0)||i%400==0)res++;
        }
        for(int i=1;i<month;i++)
        {
            res=res+mon[i];
            if(i==2&&((year%4==0&&year%100!=0)||year%400==0))res++;
        }
        return res+day;
    }
    int daysBetweenDates(string date1, string date2) {
        return abs(get(date2)-get(date1));
    }
};