[swift] LeetCode 70. Climbing Stairs

You are climbing a stair case. It takes n steps to reach to the top.

Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

func climbStairs(_ n: Int) -> Int {
    if n < 4 { return n }
    var arr = Array(repeating: 1, count: n+1)
 
    arr[2] = 2; arr[3] = 3
    for i in (4...n) {
        arr[i] = arr[i-1] + arr[i-2]
    }
 
    return arr[n]
}

（随着网站访问量的激增，服务器配置只得一再升级以维持网站不“404 Not Found”，所以网站的维护费用也在不断上涨……（目前的阿里云服务器ECS+云数据库RDS+域名购买+七牛云的费用是2200元/年），为了能不放弃该网站，所以我又把打赏链接放上来啦～所有打赏金额都会被记账并投入博客维护中，感谢厚爱，多多关照～）