【解析】使用列表 $day$ 存储每个月的天数，列表的索引就表示月份，例如 $day[1]=31$ ，就表示1月有31天。
根据这样的算法思想，不确定的就是2月的天数。可以先将2月的天数初始化为28，在输入年和月后，判断一下是否为闰年，若是，则将 $day[2]$ 的值修改为29。
最后输出 $day[month]$ 就是某年某月的天数。参考代码如下：

day=[0,31,28,31,30,31,30,31,31,30,31,30,31]
year,month=map(int,input().split())
if year%100!=0 and year%4==0 or year%400==0:
    day[2]=29
print(day[month])

#include <iostream> #include <cstdio> using namespace std; int days[12]={31,28,31,30,31,30,31,31,30,31,30,31}; int isleap(int y){ if((y%4000)|| (y%40 && y%100!=0)){ return 1;}else{ return 0;} } int main() { int year,mouth; cin>>year>>mouth; days[1]+=isleap(year); cout<<days[mouth-1]<<endl; return 0; }

叶神牛逼👍 👍

python的哦

x=int(input())

y=int(input())

if y==1 or y==3 or y==5 or y==7 or y==8 or y==10 or y==12:

    print(31)

elif y==4 or y==6 or y==9 or y==11:

    print(30)

elif ((x%4==0 and x%100!=0) or x%400==0)and y==2:

    print(29)

else:

    print(28)

#include <iostream>
using namespace std;
int day[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
int main()
{
    int year,month;
    cin>>year>>month;
    if(year%4==0 && year%100!=0){
        day[2]=29;
    }
    if(year%400==0){
        day[2]=29;
    }
    cout<<day[month]<<endl;
    return 0;
}

#include <iostream>
#include <cmath>
using namespace std;
int day[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
int main()
{
    int year,month;
    cin >>year>>month;
    if(year%400==0)day[2]=29;
    if(year%4==0 && year%100!=0)day[2]=29;
    cout<<day[month];



    return 0;
}

$\texttt{\large\color{#12a1e8}本\color{#50ce50}蒟蒻\color{#12a1e8}的第\color{#c291e8}九\color{#12a1e8}篇\color{#92a1e8}题\color{#92a9d8}解}$

${\large\color{#92a1e8}打印某年某月有几天}$

$\texttt{\color{#e57321}难度：普及-}$

last update:2023/4/2

就只是考if语句的运用而已

${\large\color{#52a1e8}Python：}$

year=int(input())
date=int(input())
if date==1 or date==3 or date==5 or date==7 or date==8 or date==10 or date==12 :
    print(31)
elif date!=2:
    print(30);
else:
    if year%400==0:
        print(29)
    elif year%4==0 and year%100!=0:
        print(29)
    else:
        print(28)

${\large\color{#52a1e8}C++：}$ 未维护的正常分支写法

#include<bits/stdc++.h>
using namespace std;
int main(){
	int a,b,c;
	cin>>a>>b;
	if(b==1||b==3||b==5||b==7||b==8||b==10||b==12){
		cout<<"31";
	}
	if(b==4||b==6||b==9||b==11){
		cout<<"30";
	}
	if(b==2){
		if(a%4==0&a%100!=0){
			cout<<"29";
		}
		if(a%100==0){
			if(a%400==0) cout<<"29";
			if(a%400!=0) cout<<"28";
		}
		if(a%4!=0){
			cout<<"28";
		}
	}
	return 0;
}

year=int(input())
month=int(input())
dic=[0,31,28,31,30,31,30,31,31,30,31,30,31]
if year%100==0:
    if year%400==0:
        dic[2]=29
elif year%4==0:
        dic[2]=29
print(dic[month])