题解 | 日期差值

#include <iostream>
#include <cmath>
using namespace std;

int days[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

int getMonthDays(int _year, int i) {
    if ((_year % 4 == 0 && _year % 100 != 0) || (_year % 400 == 0)) {
        if (i == 2) {
            return 29;
        }
    }
    return days[i];
}

long long dateToTotalDays(int date) {
    int year = date / 10000;       
    int month = (date % 10000) / 100;
    int day = date % 100;          

    long long total = 0;

    for (int y = 1; y < year; ++y) {
        total += ((y%4==0&&y%100!=0)||(y%400==0)) ? 366 : 365;
    }
  
    for (int m = 1; m < month; ++m) {
        total += getMonthDays(year, m); 
    }
 
    total += day;

    return total;
}

int main() {
    int date1, date2;

    while (cin >> date1 >> date2) {
        long long total1 = dateToTotalDays(date1);
        long long total2 = dateToTotalDays(date2);
     
        long long diff = abs(total1 - total2) + 1;
        cout << diff << endl;
    }
    return 0;
}