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.

This is not a hard question. The problem is, I really am not good at combinations...

The first fence has k way. The second fence can be the same as the first one or different from the first one. If it's the same, then no more ways. If not, there can be other (k - 1) ways. So total for the second one is k + k * (k - 1) = k  * k. From the third one, its either different from the previous one or from the second previous one. So ways[i] = (k - 1) * (ways[i - 1] + ways[i - 2]).

public int numWays(int n, int k) {
        if (n == 0) {
            return 0;
        }
        if (n == 1) {
            return k;
        }
        if (n == 2) {
            return k * k;
        }
        return (numWays(n - 2, k) + numWays(n - 1, k)) * (k - 1);
    }