题解 | #N阶楼梯上楼问题#

#include <iostream>
#include <algorithm>
using namespace std;
const int N =100;
int f[N];
int n;

int main() {
    cin >>n;
    f[1] = 1;
    f[2] = 2;
    if(n == 1||n==2) cout<< f[n];
    else{
        for(int i=3;i<=n;i++)
            f[i] = f[i-1]+f[i-2];
        cout << f[n];
    } 
}
// 64 位输出请用 printf("%lld")