【Leetcode】【Easy】Climbing Stairs

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?

 

解题：

简单的运算后，可知此题为斐波那契数列生成题。

解题步骤：

1、新建三个初始变量step1 = 1，step2 = 2，result；

2、注意算法从n = 3开始，所以当n < 3时，直接返回结果。

 

class Solution {
public:
    int climbStairs(int n) {
        int result = 0;
        int stepOne = 1;
        int stepTwo = 2;
        
        if (n == 1 || n == 2)
            return n;
        
        while (n-- && n >= 2) {
            result = stepOne + stepTwo;
            stepOne = stepTwo;
            stepTwo = result;
        }
        
        return result;
    }
};

 

附录：

斐波那契以及其他有趣数学数列