// 经典动态规划题目 f(x)=f(x−1)+f(x−2)
function climbStairs(n) {
if (n === 1) {
return 1;
}
let first = 1,
second = 2;
// 滚动数组思想
for (let i = 3; i <= n; i++) {
// 第三个数字为第一个与第二个之和
let third = first + second;
first = second;
second = third;
}
// 返回第二个
return second;
}