[Locked] Paint Fence

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.

分析：

　　这题看起来能直接用公式输出答案吧...如果觉得公式算起来麻烦，那么对于连续排列串，而且只需要得到可以涂的种类数，故应可用动态规划解决。

代码：

int totalways(int n, int k) {
    if(n == 0 || n == 1 || k == 0)
        return k;
    int ls = k, ld = k * (k - 1);
    for(int i = 2; i < n; i++) {
        int temp = ls;
        ls = ld;
        ld = (temp + ld) * (k - 1);
    }
    return ls + ld;
}