## 题目描述

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?

## 代码

```
class Solution {
public:
int climbStairs(int n) {
// IMPORTANT: Please reset any member data you declared, as
// the same Solution instance will be reused for each test case.
if(n <= 2)
return n;
int step[n];
step[0] = 1;
step[1] = 2;
for(int i = 2; i < n; i++)
{
step[i] = step[i-1] + step[i-2];
}
return step[n-1];
}
};
```