[LintCode] Climbing Stairs 爬梯子问题

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?

Have you met this question in a real interview?

YesExample

Given an example n=3 , 1+1+1=2+1=1+2=3

return 3

LeetCode上的原题，请参见我之前的博客Climbing Stairs。

解法一：

class Solution {public:    /**     * @param n: An integer     * @return: An integer     */    int climbStairs(int n) {         ) ;         vector<int> dp(n);         dp[] = ; dp[] = ;         ; i < n; ++i) {             dp[i] = dp[i - ] + dp[i - ];         }         return dp.back();    }};

解法二：

class Solution {public:    /**     * @param n: An integer     * @return: An integer     */    int climbStairs(int n) {        , b = ;        while (n--) {            b += a;            a = b - a;        }        return a;    }};