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?

DP：map[i] = map[i - 1] + map[i - 2]

public class Solution {
    //Time: O(n)  Space: O(n)
    public int climbStairs(int n) {
        int[] map = new int[n + 1];
        map[0] = map[1] = 1;
        
        for (int i = 2; i <= n; i++) {
            map[i] = map[i - 1] + map[i - 2];
        }
        return map[n];
    }
}