题解 | 跳台阶

#include <iostream>
#include<vector>
using namespace std;
#define ll long long
int main() {
    ll n;
    cin>>n;
    vector<ll>dp(n+1);
    dp[2]=1;
    if(n>2)dp[3]=2;
    for (int i = 4; i <=n; i++) {
        dp[i] = (dp[i-1] + dp[i-2]) % 998244353; 
    }
    cout<<dp[n]<<endl;
}
// 64 位输出请用 printf("%lld")