题目：
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： 此题可以由迭代或DP解决，在此贴一个 top down的DP
代码：
class Solution { public: int helper(int n, vector<int> &map){ if (n < 0) return 0; else if (n == 0) return 1; else if (map[n-1] > -1) return map[n-1]; else{ map[n-1] = helper(n-1, map)+helper(n-2, map); return map[n-1]; } } int climbStairs(int n) { vector<int> map(n,-1); return helper(n, map); } };
转载于:https://www.cnblogs.com/tanghulu321/archive/2013/04/30/3051548.html
相关资源：数据结构—成绩单生成器