[LeetCode] #70 Climbing Stairs

public class Solution {
    // f[i] = how many distinct ways from i to the top
    // f[i] = f[i + 1] + f[i + 2]
    public int climbStairs(int n) {
        if (n < 2) {
            return n;
        }
        int[] f = new int[n + 1];
        f[n] = 0;
        f[n - 1] = 1;
        if (n >= 2) {
            f[n - 2] = 2;
        }
        for (int i = n - 3; i >= 0; i--) {
            f[i] = f[i + 1] + f[i + 2];
        }
        return f[0];
    }
}