问题标题: 1367以后这题70分，求大神带我飞，三个点没超时，答案错误

#include<iostream>
#include<cstdio>
using namespace std;
int c_days[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
int main()
{   
    int year,month,day,days;
    scanf("%04d%02d%02d%d",&year,&month,&day,&days);
    if((year%4==0 && year%100!=0) || (year%400==0)) 
    c_days[2]++;
    day+=days;
    while(day>c_days[month])
    {   
        day-=c_days[month];
        month++;
        if((year%4==0 && year%100!=0) || (year%400==0)) 
        c_days[2]++;
        if(month>12)
        {
            year++;
            month=1;
        }
    }
    printf("%04d%02d%02d",year,month,day);
    return 0;
}