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?

public class Solution {
    public int climbStairs(int n) {
        if(n==1) return 1;
		int[] res = new int[2];
		res[0] = 1;
		res[1] = 2;
		while(n>2){		
			int t = res[1];
			res[1] += res[0];
			res[0] = t;
			n--;
		}
		return res[1];
    }
}