AcWing 3391. 今年的第几天？

#include<iostream>
using namespace std;
bool year(int y)//闰年返回yes,平年返回no
{
    if(y%400==0||y%4==0&&y%100!=0)
        return true;
    else
        return false;
}
int main()
{
    int y,m,d;
    int r[]={0,31,29,31,30,31,30,31,31,30,31,30,31};
    int p[]={0,31,28,31,30,31,30,31,31,30,31,30,31};

    while(cin>>y>>m>>d)
    {
        int ans=0;
        ans+=d;
        if(year(y))//闰年
        {
            for(int i=m-1;i>=1;--i)
                ans+=r[i];
        }
        else//平年
        {
             for(int i=m-1;i>=1;--i)
                ans+=p[i];
        }
        cout<<ans<<endl;
    }
    return 0;
}

AcWing 3218. 日期计算

 #include<iostream>
using namespace std;
bool year(int y)
{
    if(y%400==0||y%4==0&&y%100!=0)
        return true;//闰年
    else
        return false;//平年
}
int main()
{
    int y,d;
    int r[]={0,31,29,31,30,31,30,31,31,30,31,30,31};
    int p[]={0,31,28,31,30,31,30,31,31,30,31,30,31};

    while(cin>>y>>d)
    {
        int ans=1;
        if(year(y))
        {
            while(d>r[ans])//从一月份开始,先比较天数和当前月份的大小,天数<当前月份,说明答案就是当前月份
            {
                d-=r[ans];
                ans++;
            }
        }
        else
        {
             while(d>p[ans])
            {
                d-=p[ans];
                ans++;
            }
        }
        cout<<ans<<endl<<d<<endl;
    }

    return 0;
}

AcWing 3214. 节日

```

include[HTML_REMOVED]

using namespace std;
bool year(int y)//闰年返回yes,平年返回no
{
if(y%400==0||y%4==0&&y%100!=0)
return true;
else
return false;
}
int main()
{
int week[]={7,1,2,3,4,5,6};
int n,m;
cin>>n>>m;
int next=5;//2021-1-1是星期五
for(int i=n;i<=m;++i)
{
cout<<i<<”年:”<<next<<endl;
if(year(i))
{
next=week[(next+366)%7];
}
else
next=week[(next+365)%7];

} 
return 0;

}
```