题解 | 跳台阶

#include<bits/stdc++.h>
using namespace std;

typedef long long ll;

const int N = 2e5 + 10;
const int MOD = 998244353;

int dp[N];

int main(){
	int n;  cin >> n;
	
	dp[1] = 1,dp[2] = 1;
	
	for(int i=3 ; i <= n ; i++){
		dp[i] = (dp[i-1] + dp[i-2]) % MOD;
	}
	
	cout << dp[n];
	
	return 0;
}