text: /*
  Climbing StairsApr 3 '126879 / 13083
  
  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?
  */
  class Solution {
  public:
      int climbStairs(int n) {
          if(n<3) return n;
          vector<int> r(n);
          r[0] = 1;
          r[1] = 2;
          for(int i = 2; i<n; ++i) 
              r[i] = r[i-1] + r[i-2];
          return r[n-1];
      }
  };
  