sdnu1039
#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cmath>
#include<cstring>
using namespace std;
int main()
{
int n;
int i;
cin >> n;
int f1 = 1,f2 = 1;
int fn;
if(n<=2) cout << 1 << "\n";
else
{
for(i=3;i<=n;i++)
{
fn = f1 + f2;
f1 = f2;
f2 = fn;
}
printf("%d\n",fn);
}
return 0;
}
sdnu1083
#include<cstdio>
#include<iostream>
#include<algorithm>
using namespace std;
int main()
{
int i,n;
int fn;
while(cin>>n)
{
int f1 = 1,f2 = 2,f3 = 4;
if(n==1){
cout << "1" << "\n";continue;}
else if(n==2) {
cout << "2" << "\n";continue;}
else if(n==3) {
cout << "4" << "\n";continue;}
else
for(i = 4;i <= n;i++)
{
fn = f3 + f2 + f1;
f1 = f2;
f2 = f3;
f3 = fn;
}
cout << fn << "\n";
}
return 0;
}