题解 | 日期差值

#include <iostream>
using namespace std;
#include <vector>
void nextday(int &year,int &month,int &day){
    int monthday[12]={31,28,31,30,31,30,31,31,30,31,30,31};
    if (year%400==0||year%4==0&&year%100!=0){monthday[1]=29;}
    if (day==monthday[month-1]){
        day=1;
        month++;
    }
    else day++;
    if (month>12){
        month=1;
        year++;
    }
}
int fang(int i){
    int sum=1;
    for (int j = 0; j <i; ++j) {
        sum*=10;
    }
    return sum;
}
void get(int &year1,int &month1,int &day1,int N1){
    for (int i = 0; i < 2; ++i) {
        int temp=N1%10;
        day1=temp*fang(i)+day1;
        N1=N1/10;
    }
    for (int i = 0; i < 2; ++i) {
        int temp=N1%10;
        month1=temp* fang(i)+month1;
        N1=N1/10;
    }
    for (int i = 0; i < 4; ++i) {
        int temp=N1%10;
        year1= fang(i)*temp+year1;
        N1=N1/10;
    }
}
int main() {
    int N1,N2;
    cin>>N1>>N2;
    int year1=0,month1=0,day1=0;
    int year2=0,month2=0,day2=0;
    get(year1,month1,day1,N1);
    get(year2,month2,day2,N2);
    int sum=1;
    while (!(year1==year2&&month1==month2&&day1==day2)){
        nextday(year1,month1,day1);
        sum++;
    }
    if (sum==1){
        cout<<2;
    } else cout<<sum;
    return 0;
}