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?
1,注意函数 f（n）=f(n-1)+f(n-2)
package Leetcode; public class ClimbingStairs { public int climbStairs(int n) { if(n<=1){ return n; } int before=1; int beforebefore=1; int current=0; for(int i=2;i<=n;i++){ current=before+beforebefore; beforebefore=before; before=current; } return current; } }
原文：http://www.cnblogs.com/lilyfindjobs/p/4070940.html