动态规划算法基础篇。 

class Solution {public int climbStairs(int n) {int[] f = new int[n + 1];f[0] = 1;f[1] = 1;//当爬到n阶楼梯时，可知是由n-1阶或n-2阶楼梯而来for(int i = 2; i <= n; i++) {f[i] = f[i - 1] + f[i - 2];//后面的每一阶种数由前两个状态得到}return f[n];}
}