【LeetCode】70. 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?

【思路】斐波那契数列，第n阶是由第n-1阶和n-2阶的方法求和而成。

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