[Swift]LeetCode276. 粉刷栅栏 $ Paint Fence

佚名 6年前 (2019-04-10) 随笔 1145人围观抢沙发百度已收录

There is a fence with n posts, each post can be painted with one of the k colors.

You have to paint all the posts such that no more than two adjacent fence posts have the same color.

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Return the total number of ways you can paint the fence.

Note:

n and k are non-negative integers.

有一个有N根柱子的栅栏，每根柱子都可以涂上一种K颜色。

你必须把所有的柱子都刷上油漆，这样两个相邻的栅栏柱子就不会有相同的颜色。

返回可以绘制围栏的方法总数。

注：

n和k是非负整数。

Solution:

 1 class Solution {
 2     func numWays(_ n:Int,_ k:Int) -> Int {
 3         if n == 0 {return 0}
 4         var same:Int = 0
 5         var diff:Int = k
 6         for i in 2...n
 7         {
 8             var t:Int = diff
 9             diff = (same + diff) * (k - 1)
10             same = t
11         }
12         return same + diff
13     }
14 }