#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,m,c=0;
    long long a=1,b=1;
    cin>>n;
    if(n==1||n==2){
	   cout<<1<<" ";
	   }
	   else{
	   	for(int i=3;i<=n;i++){
       c=a+b;
       a=b;
       b=c;      
    }
    
    
    cout<<c;
	   }

    return 0;
}
`给个赞``

#include<bits/stdc++.h>	
using namespace std; 
int main(){int n,a[5050];
    cin>>n;a[1]=1;
    a[2]=1;
    for(int i
          =3;i<=n;i++){
        a[i]=a[i-2]+a[i-1];    }
    cout<<a
[n];
}

#include<bits/stdc++.h>
using namespace std;
int main(){
int a[5050],n;
cin>>n;
a[1]=1;
a[2]=1;
for(int i=3;i<=n;i++){
    a[i]=a[i-2]+a[i-1];
}
    cout<<a[n];
    return 0;
} 

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