Climbing Stairs

lc 70

You are climbing a stair case. It takes n steps to reach to the top.

Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

public class Solution {
    public int climbStairs(int n) {
        if ( n == 1 || n == 2) return n;
        int[] f = new int[n];
        f[0] = 1;
        f[1] = 2;
        for ( int i = 2; i < n; i++){
            f[i] = f[i - 1] + f[i - 2];
        }

        return f[n - 1];
    }
}