题解 | 日期差值

#include<iostream>
#include<math.h>
using namespace std;

bool isLeap(int y) {
    if ((y % 400 == 0) || (y % 100 != 0 && y % 4 == 0)) {
        return true;
    }
    else {
        return false;
    }
}

int dayofyear(int y, int m, int d) {
    static const int days[12] = { 31,28,31,30,31,30,31,31,30,31,30,31 };
    int sum = d;
    for (int i = 0;i < m - 1;i++) {
        sum = sum + days[i];
    }
    if (m > 2 && isLeap(y)) {
        sum = sum + 1;
    }
    return sum;
}

int gapsofyear(int y1, int y2) {
    int sum = 0;
    for (int i = y1;i < y2;i++) {
        if (isLeap(i)) {
            sum = sum + 366;
        }
        else {
            sum = sum + 365;
        }
    }
    return sum;
}

int main() {
    long long x;
    long long y;
    while (cin >> x >> y) {

        int year1 = x / 10000;         
        int month1 = (x / 100) % 100;
        int day1 = x % 100;     

        int year2 = y / 10000;
        int month2 = (y / 100) % 100;
        int day2 = y % 100;

        int sum1 = dayofyear(year1, month1, day1);
        int sum2 = dayofyear(year2, month2, day2);

        int gaps = gapsofyear(year1, year2);

        cout << sum2-sum1 + gaps + 1 << endl;
    }
    return 0;
}