剑指Offer——跳台阶

Question

一只青蛙一次可以跳上1级台阶，也可以跳上2级。求该青蛙跳上一个n级的台阶总共有多少种跳法。

Solution

• 递推式子 f(n) = f(n - 1) + f(n - 2)

• 解法类似于斐波那契

Code

class Solution {
public:
    int jumpFloor(int number) {
        if (number == 1)
            return 1;
        if (number == 0)
            return 0;
        if (number == 2)
            return 2;
        int one = 1;
        int two = 2;
        int sum = 0;
        for (int i = 3; i <= number; i++) {
            sum = one + two;
            one = two;
            two = sum;
        }
        return sum;
    }
};