题解 | 跳台阶

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param number int整型
     * @return int整型
     */
    public int jumpFloor (int number) {
        if (number == 1) {
            return 1;
        }
        if (number == 2) {
            return 2;
        }
        //前两步
        int prepre = 1;
        //前一步
        int pre = 2;
        for (int i = 3; i <= number; i++) {
            pre += prepre;
            prepre = pre - prepre;
        }
        return pre;
    }
}