Climbing Stairs

Problem:

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?

Analysis:

Recursive solution is slow and could not pass online judge because time limit exceeded. But I don't familiar with dynamic programming right now.

Solution:

1:  public class Solution {  
2:    public int climbStairs(int n) {  
3:      if(n==1) return 1;  
4:      if(n==2) return 2;  
5:      return climbStairs(n-1)+climbStairs(n-2);  
6:    }  
7:  }