LeetCode - Climbing Stairs

       

• Description：

      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?

     题目很好理解，类似斐波那契数列。

    

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