闰年判断
#include<bits/stdc++.h>
using namespace std;
//const int N=10001;
int n;
int main()
{
cin>>n;
if(n%400==0||(n%4==0&&n%100!=0))
cout<<"yes"<<endl;
else cout<<"no"<<endl;
return 0;
}
Fibonacci数列
#include<bits/stdc++.h>
using namespace std;
const int N=1000001;
int n;
int f[N];
int main()
{
cin>>n;
f[0]=1;
f[1]=1;
for(int i=2;i<n;i++)
f[i]=(f[i-1]+f[i-2])%10007;
cout<<f[n-1]<<endl;
return 0;
}
园的面积
#include<bits/stdc++.h>
using namespace std;
//const int N=1000001;
#define PI 3.14159265358979323;
int r;
int main()
{
cin>>r;
double ans=r*r*PI
cout<<fixed<<setprecision(7)<<ans<<endl;
return 0;
}
序列求和
#include<bits/stdc++.h>
using namespace std;
int main()
{
long long n;
cin>>n;
long long ans=(1+n)*n/2;
cout<<ans<<endl;
return 0;
}