70 爬楼梯

  1. class Solution {
  2.     public int climbStairs(int n) {
  3.         if (n == 0)
  4.             return 0;
  5.         if (n == 1)
  6.             return 1;
  7.         if (n == 2)
  8.             return 2;
  10.         int[] dp = new int[n + 1];
  11.         dp[0] = 0; dp[1] = 1; dp[2] = 2;
  12.         for (int i = 3; i <= n; i++)
  13.             dp[i] = dp[i - 1] + dp[i - 2];
  15.         return dp[n];
  16.     }
  17. }