题解 | #今年的第几天？#

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

bool run(int year){
    if(year % 4 == 0 and year % 100 !=0 or year % 400 == 0) return true;
    else return false;
}


int main(){
    int year,month,day;
    int months[13] = {0,31,28,31,30,31,30,31,31,30,31,30,31};
    while(cin >> year >> month >> day){
       if(run(year)) months[2] = 29;
       else months[2] = 28;

        int count = 0;
       for(int i = 1; i <= month-1; i ++){
            count = count + months[i];
       }
       cout << count + day << endl;
    }
}

简单题，注意闰年的判断条件

year % 4 == 0 and year % 100 !=0 or year % 400 = 0