题解 | #日期累加#

#include <iostream>
#include <cstdio>
using namespace std;
int p[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
int Run(int k)
{
    if((k%400==0)||((k%4==0)&&(k%100!=0)))return 1;
    else return 0;
}
int main() {
    int y,m,d,plus,n;
    cin>>n;
    
    while (cin >>y >> m >>d>>plus) { 
        int flag=0;
        if(Run(y)==1)p[2]=29;
        else p[2]=28;

        for(int i=m;i<=12;i++)
        {
            if(plus+d-p[i]==0)
            {
                m=i;d=p[i];
                flag=1;
                break;
            }
            else if(plus+d-p[i]<0)
            {
                m=i;d=d+plus;
                flag=1;
                break;
            }
            plus-=p[i];
        }


        while((plus+d>0)&&flag==0){
            y++;
        if(Run(y)==1)p[2]=29;
        else p[2]=28;

            for(int i=1;i<=12;i++)
            {
                if(plus+d-p[i]==0)
                {
                    m=i;d=p[i];
                    flag=1;
                    break;
                }
                else if(plus+d-p[i]<0){
                    m=i;d+=plus;
                    flag=1;
                    break;
                }
                plus-=p[i];
            }
        }

        printf("%04d-%02d-%02d\n",y,m,d);


   }
}
// 别忘了年份可能也会加