LeetCode: Climbing Stairs

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?

 

实际上是斐波那契数列，第n steps的方法为第n-1 steps和第n-2 steps的方法数之和。

处理边界条件，即n为1和n为2的时候，直接返回结果。

 

class solution{
public:
	int climbStaris(int n){
		int result;
		int lastone;
		int lasttwo;
		int i;
		if(n == 1)
		{
			return 1;
		}
		else if(n == 2)
		{
			return 2;
		}
		lastone = 2;
		lasttwo = 1;
		for(i = 2;i < n;i ++)
		{
			result = lastone + lasttwo;
			lasttwo = lastone;
			lastone = result;
		}
		return result;
	}
};