70. 爬楼梯

  1.    public int climbStairs(int n) {
  2.         int p = 1, q = 1, r = 1;
  3.         for (int i = 2; i <= n; ++i) {
  4.             p = q; 
  5.             q = r; 
  6.             r = p + q;
  7.         }
  8.         return r;
  9.     }
  1. public int climbStairs(int n) {
  2.         int[] dp = new int[n + 1];
  3.         dp[0] = 1;
  4.         dp[1] = 1;
  5.         for(int i = 2; i <= n; i++) {
  6.             dp[i] = dp[i - 1] + dp[i - 2];
  7.         }
  8.         return dp[n];
  9.     }
  11. 作者：guanpengchn
  12. 链接：https://leetcode-cn.com/problems/climbing-stairs/solution/hua-jie-suan-fa-70-pa-lou-ti-by-guanpengchn/