LeetCode OJ——Climbing Stairs

http://oj.leetcode.com/problems/climbing-stairs/

走台阶的题目，转换出数学模型之后，就是Fibonacci数列。后一个数等于前两个数的和。

递归版本超时，代码如下：

class Solution {
public:
    int walk(int sum)
    {
        if(sum ==  )
            return ;
        if(sum ==)
            return ;
        return walk(sum-)+walk(sum-);
    }

    int climbStairs(int n) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        return walk(n);
    }
};

然后改成顺序的了，AC，代码如下：

#include <iostream>

using namespace std;

class Solution {
public:

    int climbStairs(int n) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        int* arr = (int*)malloc(sizeof(int)*(n+));
        arr[] = ;
        arr[] = ;

        for(int i = ;i<=n;i++)
            arr[i] = arr[i-]+arr[i-];
        return arr[n];
    }
};

int main()
{
    Solution myS;
    int ans = myS.climbStairs();

    cout<<ans<<endl;

    return ;
}

加油！