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?
此题为典型的菲波那切数列问题；
当n=1时，有1种走法；
当n=2时，有2种走法;
当n=3时，有3种走法;
当n=4时，有5种走法；
......
当n=k时，有你n[k-1] + n[k-2]种走法；
代码如下：
1 class Solution { 2 public: 3 int climbStairs(int n) { 4 if(n == 1) 5 { 6 return 1; 7 } 8 if(n == 2) 9 { 10 return 2; 11 } 12 int a = 1; 13 int b = 2; 14 int c; 15 for(int i = 2; i < n; i++) 16 { 17 c = a + b; 18 a = b; 19 b = c; 20 } 21 return c; 22 } 23 };
原文：http://www.cnblogs.com/shellfishsplace/p/5858175.html