#include <bits/stdc++.h>

using namespace std;

int main(){ int a[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};

int n,m;

cin>>n>>m;

if(n%4==0 and n%100!=0 or n%400 == 0)

a[2]+=1;

cout<<a[m]; }

这有什么难的？

教你一排搞定！

int main(){int i,j,n;scanf("%d %d",&i,&j);while(j>12)j-=12; switch(j){case 1: n=31;break;case 2: {if(((i%4==0)&&(i%100!=00))||(i%400==0)) n=29;else n=28;}break;case 3: n=31;break;case 4: n=30;break;case 5: n=31;break;case 6: n=30;break;case 7: n=31;break;case 8: n=31;break;case 9: n=30;break;case 10: n=31;break;case 11: n=30;break;case 12: n=31;break;}printf("%d",n);return 0;}

是一排吧？

using namespace std;
int main(){
	int year,month;
	cin>>year>>month;
	if(((year%100!=0&&year%4==0)||year%400==0)&&month==2){
		cout<<29;
	}
	else if(month==1){
		cout<<31;
	}
	else if(month==2){
		cout<<28;
	}
	else if(month==3){
		cout<<31;
	}
	else if(month==4){
		cout<<30;
	}
	else if(month==5){
		cout<<31;
	}
	else if(month==6){
		cout<<30;
	}
	else if(month==7){
		cout<<31;
	}
	else if(month==8){
		cout<<31;
	}
	else if(month==9){
		cout<<30;
	}
	else if(month==10){
		cout<<31;
	}
	else if(month==11){
		cout<<30;
	}
	else if(month==12){
		cout<<31;
	}

  return 0;
}

#include<bits/stdc++.h> using namespace std; int a[13]={0,31,28,31,30,31,30,31,31,30,31,30,31}; int main(){ int n,d; cin>>n>>d; if(d2){ if(n%40 && n%100!=0||n%400==0){ cout<<29; } else{ cout<<28; } } else{ cout<<a[d]; } return 0; }