重刷蓝桥杯基础题（五）

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;
}