leetcode-70. Climbing Stairs

Description

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.

Examples

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.
4. 1 step + 1 step + 1 step
5. 1 step + 2 steps
6. 2 steps + 1 step

Solution(C++)

class Solution {
public:
    int climbStairs(int n) {
        if(n==1) return 1;
        if(n==2) return 2;
        int *p = new int[n];
        p[0] = 1;
        p[1] = 2;

        for (int i = 2; i < n; i++) {
            p[i] = p[i - 1] + p[i - 2];
        }
        return p[n - 1];
    }
};

Submition