[LeetCode] 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?

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