LeetCoder - 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?

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