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?
分析：这道题就相当于青蛙跳，就是一个费波那契数列。如果只有1级台阶，那显然只有一种跳法，如果有2级台阶，那么有两种跳的方法了:一种分两次条，每次跳一个；另外就是一次跳2级。我们把n级台阶的跳法看成是n的函数记为f(n)。当n>2时，f(n)=f(n-1)+f(n-2);
class Solution { public: int climbStairs(int n) { int result[2]={1,1}; if(n<2) return result[n]; int fibN=0; int fibOne=1; int fibTwo=1; for(unsigned int i=2;i<=n;++i) { fibN=fibOne+fibTwo; fibOne=fibTwo; fibTwo=fibN; } return fibN; } };
Climbing Stairs,布布扣,bubuko.com
原文：http://www.cnblogs.com/awy-blog/p/3589406.html