[Leetcode] Climbing Stairs

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?

int climbStairs(int n) {
        vector<int> f(n+1,0);
        for(int i=0; i<=n; i++)
        {
            if (i == 0)
                f[i] = 1;
            else if (i == 1)
                f[i] = 1;
            else
                f[i] = f[i-1] + f[i-2];
        }
        return f[n];
    }