[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?

爬台阶，你每次可以上一层或者两层，问上n层你共有多少何种方法

f(n)=f(n-1)+f(n-2)

动规，记得保存n-1和n-2的结果，直接使用递归会超时

AC代码

class Solution {
public:
    int climbStairs(int n) {
    int count[n+1];
    count[0]=0;
    count[1]=1;
    count[2]=2;
    if(n==1)
        return 1;
    if(n==2)
        return 2;
    for(int i=3;i<=n;++i)
        count[i]=count[i-1]+count[i-2];
    return count[n];
    }
};

[leetcode 70]Climbing Stairs

原文：http://blog.csdn.net/er_plough/article/details/47189081