Leetcode - Paint House II
Leetcode - Triangle

Leetcode - Paint Fence

violet posted @ May 06, 2020 07:14:20 AM in 算法 with tags Algorithm DP Golang , 235 阅读

https://leetcode.com/problems/paint-fence/

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.

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

Note:
n and k are non-negative integers.

Example:

Input: n = 3, k = 2
Output: 6
Explanation: Take c1 as color 1, c2 as color 2. All possible ways are:

            post1  post2  post3      
 -----      -----  -----  -----       
   1         c1     c1     c2 
   2         c1     c2     c1 
   3         c1     c2     c2 
   4         c2     c1     c1  
   5         c2     c1     c2
   6         c2     c2     c1

 

https://leetcode.com/problems/paint-fence/discuss/178010/The-only-solution-you-need-to-read

The best explanation!

func numWays(n int, k int) int {
    if n == 0 {
        return 0
    }
    if n == 1 {
        return k
    }
    if n == 2 {
        return k * k
    }
    dp := make([]int, n+1)
    dp[0] = 0
    dp[1] = k
    dp[2] = k*k
    for i := 3; i <= n; i++ {
        dp[i] = (dp[i-1] + dp[i-2]) * (k-1)
    }
    return dp[n]
}

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