#LeetCode# 70. Climbing Stairs

https://leetcode.com/problems/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?

Note: Given n will be a positive integer.

Example 1:

Input: 2
Output: 2
Explanation: There are two ways to climb to the top.
1. 1 step + 1 step
2. 2 steps

Example 2:

Input: 3
Output: 3
Explanation: There are three ways to climb to the top.
1. 1 step + 1 step + 1 step
2. 1 step + 2 steps
3. 2 steps + 1 step

代码：

class Solution {
public:
    int climbStairs(int n) {
        int a[10010];
        a[0] = a[1] = 1;
        for(int i = 2; i < 10010; i ++)
            a[i] = a[i - 1] + a[i - 2];
        return a[n];
    }
};