LeetCode: Climbing Stairs

Title:

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：f(n)表示到n需要的种数。考虑下到n的几种可能。实际就是两种，一种是跳一步，另一种是跳两步。所以到n需要的种数是f(n) = f(n-1)+f(n-2),所以就是斐波那契数列，代码是其非递归写法。

class Solution{
public:
int climbStairs(int n){
int *v = new int
;
v[0] = 1;
v[1] = 2;
for (int i = 2; i < n ; i++){
v[i] = v[i-1] + v[i-2];
}
return v[n-1];
}
};