70. Climbing Stairs

这个题最难的地方在于如何拼写fibonacci这个名字。

public class Solution {
    public int climbStairs(int n) {
        // dp[n] = dp[n-1] + dp[n-2];
        
        if(n <= 0) return n;
        int first = 1;
        int second = 1;
        
        for(int i = 1; i < n; i++){
            
            int temp = first + second;
            first = second;
            second = temp;
        }
        
        return second;
    }
}