题解 | 今年的第几天？

#include <bits/stdc++.h>
using namespace std;

int date[2][13]{
    {0,31,28,31,30,31,30,31,31,30,31,30,31},
    {0,31,29,31,30,31,30,31,31,30,31,30,31}
};

bool isLeapYear(int year){
    return (year%4==0&&year%100!=0)||(year%400==0);
}

int main(){
    int year,month,day;
    while(cin>>year>>month>>day){
        int j=0,ans=0;
        if(isLeapYear(year))j=1;
        for(int i=0;i<month;i++){
            ans+=date[j][i];
        }
        cout<<ans+day<<endl;
    }
}

经典模拟问题