[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?

题意: n步阶梯,你每次只能迈一步或者两步,共有几种方法;

分析: 这个问题属于动态规划问题的一种,我们可以先看一下阶梯数量较小时,存在几种方法:
阶梯数 —— 方法
n = 1: 1
n = 2: 2
n = 3: 3
n = 4: 5
通过分析: Kn = Kn-1 + Kn-2;

int climbStairs(int n) {    int stairPred = 1;      int stairNum = 1;       int k;    for (k = 2; k < n+1; k++) //迭代 Kn = Kn-1 + Kn-2;    {        int tmp = stairNum;        stairNum += stairPred;        stairPred = tmp;    }    return stairNum;}