记字节前端面试一道简单的算法题

var climbStairs = function (n) {    const memo = [];    memo[1] = 1;    memo[2] = 2;    for (let i = 3; i <= n; i++) {        memo[i] = memo[i - 2] + memo[i - 1];//所以到第n阶台阶可以从第n-2或n-1上来    }    return memo[n];};
//状态压缩var climbStairs = (n) => {    let prev = 1;    let cur = 1;    for (let i = 2; i < n + 1; i++) {        [prev, cur] = [cur, prev + cur]        // const temp = cur;   // 暂存上一次的cur        // cur = prev + cur;   // 当前的cur = 上上次cur + 上一次cur        // prev = temp;        // prev 更新为 上一次的cur    }    return cur;}

class Solution {    public int climbStairs(int n) {        int prev = 1, cur = 1;        for (int i = 2; i < n + 1; i++) {        int temp = cur;        cur = prev + cur;          prev = temp;         }        return cur;    }}