题解 | 今年的第几天？

#include<iostream>
using namespace std;
int main(){
	int Y,M,D;
	int order;
	while(cin>>Y>>M>>D){
		if((Y%4==0&&Y%100!=0)||(Y%400==0)){  //是闰年
			switch(M){
				case 1:order=D;break;
				case 2:order=31+D;break;
				case 3:order=31+29+D;break;
				case 4:order=31+29+31+D;break;
				case 5:order=31+29+31+30+D;break;
				case 6:order=31+29+31+30+31+D;break;
				case 7:order=31+29+31+30+31+30+D;break;
				case 8:order=31+29+31+30+31+30+31+D;break;
				case 9:order=31+29+31+30+31+30+31+31+D;break;
				case 10:order=31+29+31+30+31+30+31+31+30+D;break;
				case 11:order=31+29+31+30+31+30+31+31+30+31+D;break;
				case 12:order=31+29+31+30+31+30+31+31+30+31+30+D;break;
			}
		}
		else{
			switch(M){
				case 1:order=D;break;
				case 2:order=31+D;break;
				case 3:order=31+28+D;break;
				case 4:order=31+28+31+D;break;
				case 5:order=31+28+31+30+D;break;
				case 6:order=31+28+31+30+31+D;break;
				case 7:order=31+28+31+30+31+30+D;break;
				case 8:order=31+28+31+30+31+30+31+D;break;
				case 9:order=31+28+31+30+31+30+31+31+D;break;
				case 10:order=31+28+31+30+31+30+31+31+30+D;break;
				case 11:order=31+28+31+30+31+30+31+31+30+31+D;break;
				case 12:order=31+28+31+30+31+30+31+31+30+31+30+D;break;
			}
		}
		cout<<order<<endl;
	}
}