leetcode70—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

想法：动态规划分解成子问题，到达n之前，走1步或者2步。即可表示成result[n]=result[n-1]+result[n-2]

class Solution {
public:
    int climbStairs(int n) {
         == n)
            ;
        vector<);
        result[] = ;
        result[] = ;
         ; i <= n ;i++){
            result[i] = result[i-] + result[i-];
        }
        return result[n];
 
    }
};