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?

//161ms

public class Solution {    public int climbStairs(int n) {    int i = 0;    int arr[] = new int[100];    arr[0] = 0;    arr[1] = 1;    arr[2] = 2;    if (n <= 2){    return arr[n];    }    if (n > 2){    for (i = 3; i <=  n; i ++){    arr[i] = arr[i - 1] + arr[i - 2];    }    }    return arr[i - 1];      }}