java 276.画Fence.java

Posted 2021-05-08

public class Solution {
    public int numWays(int n, int k) {
        if (n < 1) return n;
        if (n == 1) return k;
        int same = k;
        int diff = k * (k - 1);
        for (int i = 2; i < n; i++) {
            int temp = same;
            same = diff;
            diff = (temp + diff) * (k - 1); 
            
        }
        return same + diff;
    }
}