comefrom: <qiyuangong>041_First_Missing_Positive_1.py
code: def firstMissingPositive( nums):
      ls = len(nums)
      index = 0
      while index < ls:
          if nums[index] <= 0 or nums[index] > ls or nums[nums[index] - 1] == nums[index]:
              index += 1
          else:
              pos = nums[index] - 1
              nums[index], nums[pos] = nums[pos], nums[index]
      res = 0
      while res < ls and nums[res] == res + 1:
          res += 1
      return res + 1
masked: def sample_funcname ( var_0 ) :
      var_2 = len ( var_0 )
      var_4 = 0
      while var_4 < var_2 :
          if var_0 [ var_4 ] <= 0 or var_0 [ var_4 ] > var_2 or var_0 [ var_0 [ var_4 ] - 1 ] == var_0 [ var_4 ] :
              var_4 += 1
          else :
              var_6 = var_0 [ var_4 ] - 1
              var_0 [ var_4 ] , var_0 [ var_6 ] = var_0 [ var_6 ] , var_0 [ var_4 ]
      var_7 = 0
      while var_7 < var_2 and var_0 [ var_7 ] == var_7 + 1 :
          var_7 += 1
      return var_7 + 1
  