Ways to Reach the n'th Stair

class Solution {
    int countWays(int n) {
        int dp[] = new int[n + 1];
        
        dp[0] = 1;
        for (int i = 1; i <= n; i++) {
            dp[i] += dp[i - 1];
            if (i > 1)
                dp[i] += dp[i - 2];
        }

        return dp[n];
    }
}