```cpp
//A0102 质数统计 埃氏筛法求解 
#include<bits/stdc++.h>
#include<cstring>
#include<stack>
#include<queue>
#include<vector>
#define ll long long
#define ld long double
#define ull unsigned long long
using namespace std;
bool tag[1086]; //0 是 1 不是 
int n;
int main(){
	cin>>n;
	for(int i=2;i<=n;i++){
		if(tag[i]==1) continue; 
		for(int j=i*2;j<=n;j+=i){
			tag[j]=1;
		}
	}
	int ans=0;
	for(int i=2;i<=n;i++){
		if(tag[i]==0) ans++;
	}
	cout<<ans; 
	return 0;
}
```

```cpp
//A0124 Pell数列 
#include<bits/stdc++.h>
#include<cstring>
#include<stack>
#include<queue>
#include<vector>
#define ll long long
#define ld long double
#define ull unsigned long long
const int maxk=1e6;
using namespace std;
int pell[maxk+86];
int n,k;
int main(){
	pell[1]=1; pell[2]=2;
	for(int i=3;i<=maxk;i++){
		pell[i]=(2*pell[i-1]+pell[i-2])%32767;
	}
	cin>>n;
	while(n--){
		cin>>k;
		cout<<pell[k]<<"\n";
	}
	return 0;
}
```

```cpp
//A0134 校门外的树 
#include<bits/stdc++.h>
#include<cstring>
#include<stack>
#include<queue>
#include<vector>
#define ll long long
#define ld long double
#define ull unsigned long long
using namespace std;
int tree[10086],L,M,st,ed; 
int main(){
	cin>>L>>M;
	for(int i=1;i<=M;i++){
		cin>>st>>ed;
		for(int j=st;j<=ed;j++){
			tree[j]=1;
		}
	}
	int ans=0;
	for(int i=0;i<=L;i++){
		if(tree[i]==0) ans++;
	}
	cout<<ans;
	return 0;
}
```

```cpp
//A0135 最长平台 
#include<bits/stdc++.h>
#include<cstring>
#include<stack>
#include<queue>
#include<vector>
#define ll long long
#define ld long double
#define ull unsigned long long
using namespace std;
int n; int a[1086]; 
int main(){
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>a[i];
	}
	int ans=1; int tmp=a[1]; int len=1;
	for(int i=2;i<=n;i++){
		if(a[i]==tmp) len++;
		else{
			tmp=a[i];
			ans=max(ans,len); len=1;
		}
	}
	cout<<ans;
	return 0;
}


```