text:  class Solution:
      def XXX(self, nums: List[int]) -> bool:
          
          def down(index):
              if index == len(nums)-1:
                  return True
              elif index > len(nums)-1:
                  return False
              else:
                  if nums[index] == 0:
                      return False
                  else:
                      for i in range(1,nums[index]+1):
                          index += i
                          if down(index):
                              return True
                          else:
                              index -= i
                      return False
          
          return down(0)
  
  