text: #include<bits/stdc++.h>
  
  using namespace std;
  
  class Solution {
  public:
      int climbStairs(int n) {
          int dp[n+1];
          dp[0] = 1;
          dp[1] = 1; 
          for(int i=2;i<=n;i++)
          {
              dp[i] = dp[i-1] + dp[i-2];
          }
          return dp[n];
      }
  };