leetcode_Climbing Stairs

描述：

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?

思路：

变形的斐波那契

代码：

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

结果：