text: class Solution:
      def missingNumber(self, nums: List[int]) -> int:
          label = [0 for i in range(len(nums) + 1)]
          for i in range(len(nums)):
              label[nums[i]] = 1
          
          for i in range(len(label)):
              if label[i] == 0:
                  ans = i
          return ans
  # ---------- 216ms, 14.8MB ----------- #
  