题解 | 数楼梯

const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void async function () {
    let line = await readline()
    let n = Number(line)
    const ans = climbStairs(n)
    console.log(ans)
}()

const climbStairs = function(n){
    const MOD = 998244353;
    let dp = []
    dp[0] = 1
    dp[1] = 1
    for(let i = 2; i<=n; i++){
        dp[i] = (dp[i-1] +dp[i-2]) %MOD
    }
    return dp[n]
}